Developer reply by Onno Ekker
Rated 5 out of 5 stars
I recently learned about this new API
https://github.com/thundernest/addon-developer-support/wiki/Using-the-WindowListener-API-to-convert-a-Legacy-Overlay-WebExtension-into-a-MailExtension-for-Thunderbird-78
which is meant to ease the migration of legacy addons to TB 78.
Maybe this is helpful for you...
Hi, I've seen the API, but even with the API it requires a significant amount of work, because of the backwards compatibility I had and the tight integration with Thunderbird with the UI and Options.
I'm working on it…
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