I cannot find a way to upload the extension .zip archive to the TFS 2017 server "Manage Extensions" page, rather than installing via .vsix.
Our "legacy controls" only build the zip format "installer", and no "Upload new extension" button appears on the Extensions Management Page to allow them to be installed as-is, like in previous TFS versions (despite membership in TF-Administrators group with [Edit instance-level information] permissions for the TF Server).
I'm hoping not to have to build out .vsix packages for all of them (ya, because I'm lazy).
Any thoughts or experience to share?