Support Import of Apple & Google's vCard v.3.0 Extension, `itemN.X-ABLabel`. Fossify Supports these as "Custom"

[DiagonalArg]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one feature request.
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Feature description

Proposal to improve consistency of Fossify with other major vCard systems: Google, Apple, (and Nextcloud):

In vCard version 3.0 as exported from Apple or Google, there is an extension, itemN.X-ABLabel which are used to label entries in a contact. ie. a phone number might be labeled "Landline", an address might be labeled "POBox" and an email address might be labeled "Secondary". Neither the stock AOSP contacts app nor Fossify display or import these correctly, though custom labels are supported when a contact is created in the app. Stock labels these as "X-" while Fossify uses "TYPE=". So:

Google (I understand it's the same for Apple):

item1.TEL:+1.610-555-1212
item1.X-ABLabel:Landline
item2.EMAIL;TYPE=INTERNET:foo@bar.com
item2.X-ABLabel:Secondary
item3.ADR:;;300 Amsterdam Av.;New York;NY;10027-2819;US
item3.X-ABLabel:POBOX
item4.URL:http\://foobar.com
item4.X-ABLabel:Art

Note that for Google, when the label is standard, eg. HOME or WORK, then it appears as:

TEL;TYPE=HOME:+1.610-555-1212
EMAIL;TYPE=INTERNET;TYPE=HOME:foo@bar.com
ADR;TYPE=HOME:;;300 Amsterdam Av.;New York;NY;10027-2819;US
URL;TYPE=HOME:http\://www.foobar.com/

Note that even this "standard" form of EMAIL is not imported/displayed correctly either by Stock or by Fossify, as the label ends up being interpreted as "Internet", not "Home". Also note that while Stock allows adding websites, Fossify does not.

When I export a contact created in the stock AOSP (GrapheneOS) contacts app, using the "custom" field for the label (other than websites, for which it is not available), it is rendered as:

TEL;X-Landline:+1-610-555-1212
EMAIL;X-Secondary:foo@bar.com
ADR;X-POBox:;;300 Amsterdam Av., New York, NY 10027-2819;;;;
URL:http\://www.foobar.com

When I export a contact created in Fossify, using the "custom" field for the label, that is rendered as:

TEL;TYPE=Landline:+1.610-555-1212
EMAIL;TYPE=Secondary:foo@bar.com
ADR;TYPE=POBox:;;300 Amsterdam Av.\, New York\, NY 10027-2819;;;;

Perhaps you'd be willing to modify Fossify to:

1. Read and display these Google/ Apple labels properly, and export them according to the vCard 4.0 TYPE= schema

2. Allow adding websites to a vCard, with custom labels. Note that the TYPE= schma is available in vCard 4.0 for URL. See the RFC.

3. This, along with a related ADR format issue should massively improve Fossify's consistency with other major vCard systems, including Nextcoud, Google, and Apple.

Thank you for a great app!

Why do you want this feature?

Compatibility.

Additional information

No response

[DiagonalArg]

In case you haven't read it, there's a study of the conflict in vCard formats here. That study includes Apple, Google, and the vCard 4.0 standard. The IETF email list has some discussion of those results.