This is the perfect add-on to manage add-ons. Of course, there is always space for a tweak here and there, but as it is, it works amazingly well and is a life saver, mainly for those that really care for their Firefox installations (auto-updating is for "lusers", there, I said it!)
Having read a lot about WebExtensions and coded some myself to check how far they can go, I realised that this add-on may be on its last days. I hope Firefox >57 will have a WE API, allowing a WE to access info of other installed WE, so this add-on could create a clone of the "about:addons" Page, without the functionality restrictions, otherwise, I will really miss it.
Thank you for one of the greatest add-ons and good luck!