Attention UXP extension developers!

[Moonchild]

Many Mozilla extensions were of multi-application target design (being usable on multiple target applications), so when you fork, you can retain or add compatibility to other applicable UXP browsers such as Basilisk. Basilisk uses Firefox's GUID so in your forked extension please only include or retain the Firefox targetApplication if your extension has been tested and is intended for Basilisk.

This is equally the case for Thunderbird's GUID (Which Interlink Mail & News retains) as our Unified Add-ons Site Backend, Phoebus, follows the same rules as the Add-ons Manager and identifies applications by their GUID. So do take care to examine your install.rdf and make sure the applications it says it is targeting are the UXP applications you actually want to target. So if you include a Firefox GUID, you target Basilisk, and if you include a Thunderbird GUID, you target Interlink.

Once again, if you do not target Basilisk or Interlink, please do not include the Firefox or Thunderbird targetApplication block, respectively!

We know of at least several Pale Moon extensions that have targetApplications for Firefox and Thunderbird that don't fully support Basilisk and Interlink respectively. This is of serious concern as of Phoebus 2.0 (which has been out for a year now).
It was asked for developers at the time to re-evaluate their install manifests but many never bothered. Now we are asking again for them to do so and issue appropriate updates if needed.