Even Firefox and Chrome's extension "stores" don't get this right. In either, a once trusted extension can be sold to a malicious company who then pushes new

Even Firefox and Chrome's extension "stores" don't get this right. In either, a once trusted extension can be sold to a malicious company who then pushes new updates which automatically get downloaded by Firefox and Chrome by default, with no warning. Quite possibly without Mozilla and Google having any way of knowing it happened at all. One way to address this is to move to a traditional "debian" style system, where packages are people affiliated with / known by Debian/Mozilla/Google, and specifically aren't the developers of the software themselves. The software is written by Developer X, but is then packaged and distributed by Packager Y, who ideally has no commercial affiliation with Developer X. If Developer X sells out to Malware Corp Z, end users can hope that Packager Y isn't part of that deal and prevents the malware from being packaged and distributed. This still isn't bullet-proof, but it's a lot better.