Notice: You have been identified as a bot, so no internal UID will be assigned to you. If you are a real person messing with your useragent, you should change it back to something normal.
I did some googling and it's apparently a security thing with no workaround.
> Anyone who tries to add an extension outside the Web Store will receive the message, "Extensions, apps, and user scripts can only be added from the Chrome Web Store. Learn more." In pointing users towards its Store, Google will focus on filtering software added there for suspect code.
> Individuals or companies hosting legitimate extensions on their own websites will need to add these to the Store or use inline installation (where apps appear to be hosted on a site but are actually on Google's Store).
Anonymous A (OP) replied with this 14 years ago, 2 minutes later, 1 hour after the original post[^][v]#339,011