Glossary
Install-Time Permission
An install-time permission is granted in a single bundled request at the moment an extension or application is installed, before it's actually used for anything — the user approves the entire requested set up front, once, rather than being asked about each capability at the point it's actually exercised. This is simple to implement and simple for a user to get through quickly, which is exactly what makes it easy to over-grant: a user facing one bundled prompt has little practical way to approve only the specific capabilities they actually care about while declining the rest.
Because the request happens before the user has any concrete experience of what the extension actually does, it's also poorly timed for genuinely informed judgment — approving broad access to something not yet used is a much less informed decision than approving a specific capability at the moment its purpose is concretely apparent.