Rated 5 out of 5 stars
Since there is no official way to contact the developer via support channels (no forum or email address), these form is used, which is a valid step according to AMO rules.
1. this add-on breaks Stylish add-ons user styles, which can not be edited anymore). To fix this the css code has to be modified like this:
#addons-page .addon[status="installed"] ----->
2. there already is an add-on on AMO, that restores the version number inside add-ons manager for Firefox, Thunderbird and Seamonkey.
Keep up your great work.
Thank you for your review and advice!
I fixed the css code as you wrote. I appreciate your excellent work and add-ons. Thank you.