@m4zuper The extensions were not installing when pasting their links in Browser Settings. But they are installing when pasting their IDs only.
So instead of using https://chromewebstore.google.com/detail/hunter-email-finder-exten/hgmhmanijnjhaffoampdlllchpolkdnj, one should just paste this in the Browser Settings, in the Extensions field: hgmhmanijnjhaffoampdlllchpolkdnj
Another question would be how to uninstall an extension from a BAS profile?