Data for legacy version of webextension.api.userScripts

[rebloor]

Summary

Initial PR for addressing the compatibility data needs of Bug 1943050 Enable userScripts API by default. This PR creates the compatibility data to complement the documentation changes in mdn/content#37975:

• addition of a userScripts_legacy.json file (being a copy of the original userScripts.json with a note about the legacy version availability in Manifest V2 only)
• update to user_scripts.json to note its applicability to Manifest V2 only.

[rebloor]

On reflection, don't believe this is the right approach.

[Rob--W]

mdn_url is missing everywhere. Is that intended?

Other than that, this looks good at the surface.

[caugner]

I assume you aligned on this approach with @Rob--W on Monday.

If the only overlap between the old and the new API is register(), then an alternative solution would be to mark all methods from the old API as deprecated, and only rename the legacy register BCD feature to register_legacy (with a good description).

Anyways, if we decide to introduce webextensions.api.userScripts_legacy, then shouldn't webextensions.api.userScripts reflect support for the new API, even if that's currently false for everything?

/cc @Elchi3 in case he has other ideas for this case.

[rebloor]

mdn_url is missing everywhere. Is that intended?

@Rob--W mdn_url is filled when a page referencing the BCD key goes live. Until then, you get a warning from the linter: ✖ webextensions.api.userScripts_legacy - Warning → Current mdn_url is a 404: https://developer.mozilla.org/docs/Mozilla/Add-ons/WebExtensions/API/userScripts_legacy

[rebloor]

@caugner

I assume you aligned on this approach with @Rob--W on Monday.

Yes

Anyways, if we decide to introduce webextensions.api.userScripts_legacy, then shouldn't webextensions.api.userScripts reflect support for the new API, even if that's currently false for everything?

I'm working on a PR to add the documentation for the new API now and will update the BCD shortly.

[caugner]

LGTM from a structure point of view, didn't verify the accurateness of the data.

[caugner]

I'm holding off on merging this until @dotproto or @Rob--W have approved.

[Rob--W]

Is this a good place for adding a reference to the newer userScripts APIs for future reference?

I.e. a comment to the top level userScripts namespace, register method, RegisteredUserScripts, RegisteredUserScript.unregister methods.

[Rob--W]

When I read this out of context, it could be read as the API being meant for extensions using MV3, and that there is more information at the given link. Is this just me?

A way to address that is to prepend a note like "Only available for use in extensions using Manifest V2."

[rebloor]

On rereading - I can only agree!

Suggested change

	"notes": "For extension using Manifest V3, see [`userScripts.unregister`](https://developer.mozilla.org/docs/Mozilla/Add-ons/WebExtensions/API/userScripts/unregister)."
	"notes": "Only available for use in extensions using Manifest V2. For extension using Manifest V3, see [`userScripts.unregister`](https://developer.mozilla.org/docs/Mozilla/Add-ons/WebExtensions/API/userScripts/unregister)."