Add Facebook Mobile in-app browser detection

[Copilot]

Facebook's in-app browser on iOS/Android was not being detected, causing web apps opened from Facebook links to be misidentified.

Changes

• Browser detection (parser-browsers.js): Added descriptor matching [FBAN/ marker (covers both FBIOS and FB4A variants), extracting version from FBAV/ parameter when present
• Aliases (constants.js): Added facebook ↔ Facebook Mobile mappings for satisfies() support
• Test coverage (useragentstrings.yml): Added cases for iOS (iPhone/iPad) and Android, including version and no-version variants

Example

const ua = 'Mozilla/5.0 (iPhone; CPU iPhone OS 14_6 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148 [FBAN/FBIOS;FBAV/328.0.0.29.120]';

Bowser.parse(ua).browser.name;  // "Facebook Mobile"

Bowser.getParser(ua).satisfies({ facebook: '>300' });  // true

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• developers.whatismybrowser.com
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Identifying Facebook Mobile</issue_title>
<issue_description>It's an edge case, as the facebook app tends to use the browsers available on the device for external links (works fine on Android devices). But it seems this is not the case if used on IPhones. As a result it's possible for any web app to be displayed via "facebook mobile" if linked there from the app.

Would it be possible for this detection to be added to bowserjs?

window.navigator.userAgent of the browser is:
see https://developers.whatismybrowser.com/useragents/explore/software_name/facebook-app/

</issue_description>

Comments on the Issue (you are @copilot in this section)

@lancedikson Hi @anderschbe. Check out the #140 issue, please. It seems to be related to that one in general. It would be possible to come up with some solution, but I'm afraid I don't have much time to develop it. Only if somebody could help me out with arranging and systemizing all the knowledge about how different FB can mark their stuff in UA strings :)

• Fixes Identifying Facebook Mobile #367

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