Several popular Firefox privacy/security add-ons have become much worse in the last year. BlockSite added ads and full tracking of user browsing. (That one is really bad.) AdBlock Plus added a "whitelist" of ads they let through. (The advertisers pay AdBlock)
Firefox itself reports installed add-ons to Mozilla AMO each day for tracking and update purposes. Add-ons don't need to check for updates themselves.
AdBlock Plus is published under a GPLv3 license, so it is open source even if it doesn't have your preferred default settings. AdBlock Edge is a fork of AdBlock Plus that just disables the acceptable ads preference.
Personally, I don't use AdBlock Plus, but I think it is silly to criticize it for allowing some ads. Even in the first version it had a preference for allowing Google text ads -- the developers have always presented it as a tool for blocking annoying ads, not as a means for blocking all ads. That said, it is very easy to subscribe to another filter list in AdBlock Plus that blocks all ads.
It's not in the source code, but instead in a subscription that ABP uses by default (it remembers if you unchecked "Allow some non-intrusive advertising" so it doesn't re-enable this list on every update): https://adblockplus.org/en/acceptable-ads
I don't know if disconnect.me is an exact alternative to AdBlock since I have never used AdBlock, but I like what it's doing and it's open source.
https://disconnect.me/opensource
Adblock Edge is a fork of Adblock Plus without the whitelisted ads, although I don't really see the point as the whitelist can be disabled from a simple checkbox in settings.
Firefox itself reports installed add-ons to Mozilla AMO each day for tracking and update purposes. Add-ons don't need to check for updates themselves.