Update many broken links, update outdated docs etc. (#6153)

Also,
- update list of contributors in COPYRIGHT file
- update GPL 2.0 text to current version (with a URL instead
  of a postal address)
- clarify copyright statement in the manual
- remove invalid or misleading licensing conditions beyond GPL
- add the names of Fedora packages needed by several of
  our packages (complementing the Debian and Homebrew names
  already listed)
- replace outdated information about the GAP website in the dev manual
- remove empty chapter about git in the dev manual

Author: fingolfin

.mailmap

@@ -37,6 +37,7 @@ Max Neunhöffer <[email protected]>
 Michael Young <[email protected]>
 Paula Hähndel <[email protected]>
 Russ Woodroofe <[email protected]>
+Sam Tertooy <[email protected]>
 Sebastian Gutsche <[email protected]> <[email protected]>
 Sergio Siccha <[email protected]>
 Sergio Siccha <[email protected]> <[email protected]>

CONTRIBUTING.md

@@ -8,7 +8,7 @@ possible.
 ## Packages versus contributions to the "core" system
 
 One way of contributing to GAP is to write a
-[GAP package](https://www.gap-system.org/Packages/packages.html) and send it
+[GAP package](https://www.gap-system.org/packages/authors/) and send it
 to us to consider for redistribution with GAP.  This is appropriate if your
 contribution adds a body of functionality for some area of mathematics (or
 some coherent batch of system functionality). A package is also appropriate

COPYRIGHT

@@ -11,20 +11,21 @@ or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
 License for more details.
 
 You should have received a copy of the GNU General Public License
-along with GAP; if not, write to the Free Software Foundation, Inc.,
-51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+along with GAP; if not, see <https://www.gnu.org/licenses/>.
 
 
-Copyright (C) 1988-2024 by its authors, which include:
+Copyright (C) 1988-2025 by its authors, which include:
 
 * Ákos Seress
 * Alex Wegner
 * Alexander Hulpke
 * Alice Niemeyer
+* Anakin Dey
 * Andreas Distler
 * Andrew Solomon
 * Anna Sucker
 * Ansgar Kaup
+* Arhan Chaudhary
 * Arne Storjohann
 * Bernhard Reinke
 * Bettina Eick
@@ -47,7 +48,7 @@ Copyright (C) 1988-2024 by its authors, which include:
 * Dmitrii Pasechnik
 * Dominik Bernhardt
 * Emma Ahrens
-* Erik M. Bray
+* E. Madison Bray
 * Erzsébet Horváth
 * Etaoin Shrdlu
 * Fabian Zickgraf
@@ -69,9 +70,11 @@ Copyright (C) 1988-2024 by its authors, which include:
 * Isabel M. Araújo
 * Isuru Fernando
 * Jack Schmidt
+* Jake Faulkner
 * James Mitchell
 * James Williams
 * Jan de Muijnck-Hughes
+* Jan Engelhardt
 * Jendrik Brachter
 * Jens Brandt
 * Jens Hollmann
@@ -80,11 +83,13 @@ Copyright (C) 1988-2024 by its authors, which include:
 * Jerry James
 * Jesse Lansdown
 * Joachim Neubüser
+* Joe Edwards
 * Johannes Meier
 * John McDermott
 * Jürgen Mnich
 * Jürgen Müller
 * Juergen Wisliceny
+* Lars Göttgens
 * Laurent Bartholdi
 * Lucas Jones
 * Lucas Wollenhaupt
@@ -109,13 +114,16 @@ Copyright (C) 1988-2024 by its authors, which include:
 * Paula Hähndel
 * Ramón Esteban Romero
 * Reimer Behrends
+* Reinis Cirpons
 * Rob Wainwright
 * Robert Arthur
 * Robert F. Morse
 * Russ Woodroofe
 * Ruth Hoffmann
+* Sam Tertooy
 * Sandeep Murthy
 * Sarah Rees
+* Scott Brenner
 * Scott Murray
 * Sebastian Gutsche
 * Sergio Siccha
@@ -126,6 +134,7 @@ Copyright (C) 1988-2024 by its authors, which include:
 * Thomas Bischops
 * Thomas Breuer
 * Thomas Merkwitz
+* Torben Wiedemann
 * Udo Polis
 * Ute Schiffer
 * VInay Wagh

INSTALL.md

@@ -22,13 +22,14 @@ for Windows.
 Alternative installation methods which aim to simplify the installation
 mostly by offering precompiled binaries are:
 
+* Several Linux distributions such as Debian/Ubuntu or Fedora have
+  packaged GAP itself; see e.g. <https://repology.org/project/gap/versions>
 * GAP installer for Homebrew (package manager for macOS)
 * Docker image for GAP and most of the packages
 * the rsync-based binary distribution for Linux
 
 Note, however, that these are updated independently and may not yet provide
-the latest GAP release. Further details are available on the GAP website
-here: <https://www.gap-system.org/Download/alternatives.html>.
+the latest GAP release.
 
 
 1 Installation Overview
@@ -49,9 +50,9 @@ section "Installing required dependencies" in the file `README.md`.
 To get maximum benefit from GAP and from various packages, we recommend
 to install a number of other free software libraries (and their associated
 development tools) although they are not required for basic operation.
-See <https://www.gap-system.org/Download/tools.html> for more details.
+See Section "Compilation" below for more details.
 
-The installation consists of five easy steps:
+The installation consists of five steps:
 
 1. Get the archive suitable for your system
 2. Unpack the archive in the directory where you wish to install GAP
@@ -76,7 +77,7 @@ common problems with the installation.
 =====================
 
 You can get archives for the GAP distribution from the GAP website at
-<https://www.gap-system.org/Releases/>. If you use Unix (including macOS),
+<https://www.gap-system.org/install/>. If you use Unix (including macOS),
 you need to download the GAP source distribution, that is, a file named
 
     gap-4.X.Y.tar.bz2
@@ -147,7 +148,7 @@ On Ubuntu or Debian, you can install these with the following command:
 
 On Fedora:
 
-    sudo dnf install gcc gcc-c++ make autoconf gmp gmp-devel readline readline-devel zlib zlib-devel
+    sudo dnf install gcc gcc-c++ make autoconf gmp-devel readline-devel zlib-devel
 
 On Alpine:
 
@@ -164,27 +165,35 @@ prerequisites. Here is an incomplete list of GAP packages and their requirements
 
 - 4ti2Interface
   - Debian/Ubuntu: 4ti2
+  - Fedora: 4ti2-devel
   - Homebrew: (not currently available)
 - alnuth
   - Debian/Ubuntu: pari-gp
+  - Fedora: pari-gp
   - Homebrew: pari
 - browse
   - Debian/Ubuntu: libncurses-dev
+  - Fedora: ncurses-devel
   - Homebrew: ncurses
 - CddInterface
   - Debian/Ubuntu: libcdd-dev
+  - Fedora: cddlib-devel
   - Homebrew: cddlib
 - curlInterface
   - Debian/Ubuntu: libcurl4-openssl-dev
+  - Fedora: curl-devel
   - Homebrew: curl
 - float
   - Debian/Ubuntu: libfplll-dev libmpc-dev libmpfi-dev libmpfr-dev
+  - Fedora: fplll libmpc-devel mpfi-devel mpfr-devel
   - Homebrew: fplll libmpc mpfi mpfr
 - singular
   - Debian/Ubuntu: singular
+  - Fedora: Singular
   - Homebrew: singular
 - ZeroMQInterface
   - Debian/Ubuntu: libzmq3-dev
+  - Fedora: zeromq-devel
   - Homebrew: zmq
 
 
@@ -411,7 +420,7 @@ found at <https://gap-packages.github.io/>.
 Congratulations, your installation is finished.
 
 Once the installation is complete, you may wish to subscribe to the
-[GAP forum mailing list](https://www.gap-system.org/Contacts/Forum/forum.html),
+[GAP forum mailing list](https://www.gap-system.org/forum/),
 which provides help with user questions of a general nature. You can also
 chat with us on [Slack](https://gap-system.org/slack). Bug reports and other
 problems you have while installing and/or using GAP should be reported via
@@ -465,7 +474,7 @@ the help system which provides useful search features.
 
 This section lists a few common problems when installing or running GAP and
 their remedies. Also see the FAQ list on the GAP web pages at
-<https://www.gap-system.org/Faq/faq.html>.
+<https://www.gap-system.org/faq/>.
 
 ### GAP starts with a warning `hmm, I cannot find lib/init.g`
 

LICENSE

@@ -2,7 +2,7 @@
                        Version 2, June 1991
 
  Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ <https://fsf.org/>
  Everyone is permitted to copy and distribute verbatim copies
  of this license document, but changing it is not allowed.
 
@@ -304,8 +304,7 @@ the "copyright" line and a pointer to where the full notice is found.
     GNU General Public License for more details.
 
     You should have received a copy of the GNU General Public License along
-    with this program; if not, write to the Free Software Foundation, Inc.,
-    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+    with this program; if not, see <https://www.gnu.org/licenses/>.
 
 Also add information on how to contact you by electronic and paper mail.
 
@@ -329,8 +328,8 @@ necessary.  Here is a sample; alter the names:
   Yoyodyne, Inc., hereby disclaims all copyright interest in the program
   `Gnomovision' (which makes passes at compilers) written by James Hacker.
 
-  <signature of Ty Coon>, 1 April 1989
-  Ty Coon, President of Vice
+  <signature of Moe Ghoul>, 1 April 1989
+  Moe Ghoul, President of Vice
 
 This General Public License does not permit incorporating your program into
 proprietary programs.  If your program is a subroutine library, you may

README.md

@@ -10,11 +10,11 @@
 GAP is a system for computational discrete algebra, with particular emphasis
 on computational group theory. GAP provides a programming language, a library
 of thousands of functions implementing algebraic algorithms written in the GAP
-language as well as large data libraries of algebraic objects. For a more
-detailed overview, see
-  <https://www.gap-system.org/Overview/overview.html>.
+language as well as large data libraries of algebraic objects. For some more
+information, see
+  <https://www.gap-system.org/about/>.
 For a description of the mathematical capabilities, see
-  <https://www.gap-system.org/Overview/Capabilities/capabilities.html>.
+  <https://www.gap-system.org/capabilities/>.
 
 GAP is used in research and teaching for studying groups and their
 representations, rings, vector spaces, algebras, combinatorial structures, and
@@ -26,9 +26,8 @@ easily modify or extend it for your special use.
 
 ## Download a stable release version
 
-The latest stable release of the GAP system, including all currently
-redistributed GAP packages, can be obtained from
-  <https://www.gap-system.org/Releases/index.html>.
+The latest stable release of the GAP system can be obtained from
+  <https://www.gap-system.org/install/>.
 Afterwards, follow the instructions in the file `INSTALL.md` in the GAP root
 directory.
 
@@ -69,7 +68,7 @@ On Ubuntu or Debian, you can install these with the following command:
 
 On Fedora:
 
-    sudo dnf install gcc gcc-c++ make autoconf gmp gmp-devel readline readline-devel zlib zlib-devel
+    sudo dnf install gcc gcc-c++ make autoconf gmp-devel readline-devel zlib-devel
 
 On Alpine:
 
@@ -134,18 +133,13 @@ please read the [contributor guidelines](CONTRIBUTING.md). Additional informatio
 
 To keep up to date on GAP news (discussion of problems, release announcements,
 bug fixes), you can subscribe to the
-[GAP forum](https://www.gap-system.org/Contacts/Forum/forum.html) and
+[GAP forum](https://www.gap-system.org/forum/) and
 [GAP development](https://lists.uni-kl.de/gap/info/gap) mailing lists,
-notifications on GitHub, and chat with us on [Slack](https://gap-system.org/slack).
+notifications on GitHub, or chat with us on [Slack](https://gap-system.org/slack).
 
-If you have any questions about working with GAP, you can ask them on
-[GAP forum](https://www.gap-system.org/Contacts/Forum/forum.html) (requires subscription)
-or [GAP support](https://www.gap-system.org/Contacts/People/supportgroup.html) mailing lists.
-
-Please tell us about your use of GAP in research or teaching. We maintain a
-[bibliography of publications citing GAP](https://www.gap-system.org/Doc/Bib/bib.html).
-Please [help us](https://www.gap-system.org/Contacts/publicationfeedback.html)
-keeping it up to date.
+If you have any questions about working with GAP, you can ask them on the
+[GAP forum](https://www.gap-system.org/forum/) mailing list (requires subscription)
+or [use one of our various support channels](https://www.gap-system.org/issues).
 
 
 # License

doc/dev/git.xml

@@ -47,7 +47,6 @@ there is a concept of <E>modules</E> where  parts of the
 <#Include SYSTEM "lib.xml">
 <#Include SYSTEM "documentation.xml">
 <#Include SYSTEM "testing.xml">
-<#Include SYSTEM "git.xml">
 <#Include SYSTEM "pkgdist.xml">
 <#Include SYSTEM "website.xml">
 <#Include SYSTEM "newcode.xml">

doc/dev/main.xml

@@ -42,8 +42,7 @@ Moreover, it is recommended to group tests that require packages to be
 performed after all other tests are completed.
 
 The directory <F>tst/testinstall</F> contains a subset of tests which are
-recommended after installing &GAP;,
-see <URL>https://www.gap-system.org/Download/INSTALL</URL>.
+recommended after installing &GAP;.
 The idea is that the examples in these <C>.tst</C> files are typical
 &GAP; computations,
 and that running these tests requires only a few minutes.