Callback-url-file-3a-2f-2f-2fproc-2fself-2fenviron -

: Many applications store credentials in environment variables.

| Encoded | Decoded | |---------|---------| | 3A | : | | 2F | / | | 2F | / | | 2F | / | callback-url-file-3A-2F-2F-2Fproc-2Fself-2Fenviron

: Environment variables often include data from HTTP headers, such as the User-Agent . Technical Analysis

URI scheme to point the server to its own internal process information. 1. Breakdown of the Components callback-url= or internal configuration paths.

I notice you're asking about a callback URL that points to a local file path ( /proc/self/environ ), which contains environment variables of the current process. This pattern raises security concerns, as it resembles:

To read the process's environment variables, which often contain sensitive data such as API keys, session tokens, or internal configuration paths. Technical Analysis