Hasn't worked since before Firefox 90

[CinderBH]

It simply stopped working around then. The "Add Feed" icon is gone, and even adding them manually in the options does nothing, even though they show up in the options menu.

I tried uninstalling and reinstalling it, and also creating a fresh profile with only Livemarks installed. Still nothing.

Here's a cap of the console errors.

[evilpie]

The RSS feed you are trying to view doesn't exist: https://mangadex.org/rss/nfWCXKSze3xGRDTOWBNE7CFMURYGMVQU/group_id/13132h=1

Seems like they are gone: https://www.reddit.com/r/mangadex/comments/u7pcoi/rss/.

[CinderBH]

Please reopen because this isn't an issue of a single RSS, it's the entire extension not working as intended.

[evilpie]

Do you see any error in the web console of the settings page when clicking the "New livemark" button?

[evilpie]

"options does nothing, even though they show up in the options menu." What does this mean? Do they not show up as bookmarks?

[CinderBH]

Yes, if I try to add them they show up in the list in the extension's option screen, but not the bookmarks bar or menu.

Also, I tried and the two big standout errors are these:

Some cookies use the recommended "SameSite" attribute incorrectly 20
The "cookietest" cookie does not have a valid value for the "SameSite" attribute. Soon cookies without the "SameSite" attribute or with an invalid value will be handled as "Lax". This means that the cookie will no longer be sent in third-party contexts. If the application depends on the availability of this cookie in this type of context, add the "SameSite=None" attribute. For more information on the "SameSite" attribute, see https://developer.mozilla.org/docs/Web/HTTP/Headers/Set-Cookie/SameSite

The "ldsuid" cookie was rejected because a non-HTTPS cookie cannot be set as "secure".

[evilpie]

I doubt these errors are actually related, otherwise adding the feeds would probably fail anyway. Can you try creating a new profile (e.g. with about:profiles) and see if the extension works there?

[evilpie]

Oh and it would be good if you could run https://firefox-storage-test.glitch.me/ in your normal profile to check if something with your storage is broken.

[CinderBH]

The profile thing I already tried, and it didn't work. Anyway, I tried the site and this was the result.

Overview:
Storage is broken. This is your first visit or all storage was automatically cleared.
Specific Subsystem Statuses:

LocalStorage
Good: Totally Working. (fullyOperational)
QuotaManager
Good: Totally Working. (fullyOperational)
IndexedDB
Good: Totally Working. (fullyOperational)
Cache API
Bad: Our test logic is broken, please copy and paste the contents of 'Debug Info' below and anything in the devtools console and send to :asuth. (unexpectedBreakage)

Debug Info:

NetworkError when attempting to fetch resource.

{
"v": 1,
"curVersion": 102,
"prevVersion": 0,
"ls": {},
"qm": {
"lastWorkedIn": 102
},
"idb": {
"persistentCreatedIn": 102,
"persistentLastOpenedIn": 102,
"clearDetectedIn": 0
},
"cache": {
"firstCacheCreatedIn": 0,
"unpaddedOpaqueCreatedIn": 0,
"paddedOpaqueCreatedIn": 0
}
}

[evilpie]

Sorry. I probably won't be able to help you.

[CinderBH]

Eh? What do you mean?