So, I received Firefox 66.0.4 on my desktop, and the release notes
indicates this carries a fix for the issue. After updating, I can confirm that all my add-ons are working, with no action required on my side.
Ditto on Android, I received an update for Firefox, and add-ons are working on Android as well. All but one add-ons were automatically re-enabled, I only had to do so for one (a theme/skin named Black by MaDonna).
Good to see it fixed in a reasonably timely manner (especially with a weekend in the midst), but I'm sure there's a bit of egg on Mozilla's face, as they join the list of big-name companies that forgot to renew something (cert, domain, etc.)
Edit: this release has a few unresolved issues:
- A small number of add-ons may be listed as unsupported or may not appear in about:addons. Their data is not lost; users should be able to re-install the add-ons and recover the data (Bug 1549129).
- If add-ons that use Containers functionality (such as Multi-Account Containers and Facebook Container) were disabled as part of this problem, any lost site data or custom configurations for those add-ons will not be recovered by this release. Users may need to set them up and login again in about:addons (Bug 1549204).
- Themes may not be re-enabled. Users may need to re-enable them in about:addons (Bug 1549022).
- Home page or search settings customized by an add-on may be reset to defaults. Users may need to customize them again in about:preferences or about:addons (Bug 1549192).