Modify Safari storage quota based on WebKit resource (mdn#40575)

* modify Safari storage quota to be accurate

* Update files/en-us/web/api/storage_api/storage_quotas_and_eviction_criteria/index.md

Co-authored-by: Josh Kelley <joshkel@gmail.com>

* resolve concern with "browser and web apps"

* Update index.md

* Update files/en-us/web/api/storage_api/storage_quotas_and_eviction_criteria/index.md

Co-authored-by: wbamberg <will@bootbonnet.ca>

* Update files/en-us/web/api/storage_api/storage_quotas_and_eviction_criteria/index.md

Co-authored-by: wbamberg <will@bootbonnet.ca>

* Update files/en-us/web/api/storage_api/storage_quotas_and_eviction_criteria/index.md

Co-authored-by: wbamberg <will@bootbonnet.ca>

* Update files/en-us/web/api/storage_api/storage_quotas_and_eviction_criteria/index.md

Co-authored-by: wbamberg <will@bootbonnet.ca>

* Update files/en-us/web/api/storage_api/storage_quotas_and_eviction_criteria/index.md

* Update files/en-us/web/api/storage_api/storage_quotas_and_eviction_criteria/index.md

---------

Co-authored-by: Josh Kelley <joshkel@gmail.com>
Co-authored-by: wbamberg <will@bootbonnet.ca>

Author: 3 people

files/en-us/web/api/storage_api/storage_quotas_and_eviction_criteria/index.md

@@ -107,14 +107,32 @@ Like with Firefox, because this quota is calculated based on the hard drive tota
 
 #### Safari
 
-Starting with macOS 14 and iOS 17, Safari allots up to around 20% of the total disk space for each origin. If the user has saved it as a web app on the Home Screen or the Dock, this limit is increased to up to 60% of the disk size. For privacy reasons, {{Glossary("Same-origin policy", "cross-origin")}} frames have a separate quota, amounting to roughly 1/10 of their parents.
+Webkit imposes different quotas for _browser apps_ and for other applications which can embed web content (for example, apps that use WKWebView). A browser app is an application that can be set as the system’s default browser. This includes Safari and some other WebKit-based third-party browsers.
 
-For instance, a macOS device with a 1 TiB drive will limit each origin to around 200 GiB. If the user stores a web app on its Dock, that will be allotted a greater limit of around 600 GiB.
+Starting with macOS 14 and iOS 17:
 
-Like other browsers, the exact limits enforced by the quota may vary as to avoid fingerprinting. Additionally, Safari also enforces an overall quota that stored data across all origins cannot grow beyond: 80% of disk size for each browser and web app, and 15% of disk size for each non-browser app that displays web content. More info on Safari's storage policies can be found on the [WebKit blog](https://www.webkit.org/blog/14403/updates-to-storage-policy/).
+- For Webkit-based browser apps, each origin can store up to around 60% of total disk.
+- For other Webkit-based apps that embed web content, each origin can store up to around 15%  of total disk. If the user has saved the site as a web app on the Home Screen or the Dock, it uses the same origin quota as the browser app (around 60% of disk space).
+
+For instance, a macOS device with a 1 TiB drive will limit each origin within the Safari web browser to around 600 GiB. Origins running in another app's embedded WebView will be allotted a lesser limit of around 150 GiB.
+
+For privacy reasons, {{Glossary("Same-origin policy", "cross-origin")}} frames have a separate quota, amounting to roughly 1/10 of their parents.
+
+Like other browsers, the exact limits enforced by the quota may vary so as to avoid fingerprinting.
+
+WebKit also enforces an overall quota that stored data across all origins cannot grow beyond 80% of disk size for browser apps, and 20% of disk size for non-browser apps that display web content.
+
+More information on WebKit's storage policies can be found on the [WebKit blog](https://www.webkit.org/blog/14403/updates-to-storage-policy/).
 
 In earlier versions of Safari, an origin is given an initial 1 GiB quota. Once the origin reaches this limit, Safari asks the user for permission to let the origin store more data. This happens whether the origin stores data in best-effort mode or persistent mode.
 
+> [!NOTE]
+>  On iOS/iPadOS, third-party browsers have historically had to use WebKit, so these WebKit quotas apply to them as well as Safari. In the EU (iOS 17.4+), Apple permits alternative browser engines; in such cases, those browsers’ own engine policies apply instead of WebKit’s.
+>
+> On macOS, non-WebKit browsers (e.g., Chromium/Firefox) use their own storage policies.
+>
+> More info on the EU-specific information can be found on [Apple Developer Support Page](https://developer.apple.com/support/alternative-browser-engines).
+
 ## How to check the available space?
 
 Web developers can check how much space is available for their origin and how much is being used by the origin with the {{domxref("StorageManager.estimate()", "navigator.storage.estimate()")}} method of the {{domxref("Storage_API", "Storage API", "", "nocode")}}.