Can't install themes.

Icecat's behavior is really weird:

When you install a *.xpi theme, Icecat will check the key id. But themes don't have that property.

If you add that and compile from source, it works without any issues.

vcxsrv_mXuc8eAggA

But still, do this will output some warning:

1557641899973   addons.webextension.<unknown>   WARN    Loading extension 'null': Reading manifest: Error processing id: An unexpected property was found in the WebExtension manifest.
1557641900095   addons.webextension.<unknown>   WARN    Loading extension 'null': Reading manifest: Error processing id: An unexpected property was found in the WebExtension manifest.
1557641900111   addons.webextension.<unknown>   WARN    Loading extension 'null': Reading manifest: Error processing id: An unexpected property was found in the WebExtension manifest.
1557641900439   addons.xpi      WARN    Please specify whether you want browser_style or not in your options_ui options.
1557641900537   addons.xpi      WARN    Please specify whether you want browser_style or not in your options_ui options.
1557641900544   addons.webextension.<unknown>   WARN    Loading extension 'null': Reading manifest: Error processing id: An unexpected property was found in the WebExtension manifest.
1557641900572   addons.webextension.<unknown>   WARN    Loading extension 'null': Reading manifest: Error processing id: An unexpected property was found in the WebExtension manifest.

Close it and reopen, this will not show again.

Edited by Kiryuu Sakuya