BORG_DEBUG_PASSPHRASE: also show "other" env vars, docs

docs/usage/general/environment.rst.inc

@@ -36,6 +36,8 @@ General:
         Main usecase for this is to automate fully ``borg change-passphrase``.
     BORG_DISPLAY_PASSPHRASE
         When set, use the value to answer the "display the passphrase for verification" question when defining a new passphrase for encrypted repositories.
+    BORG_DEBUG_PASSPHRASE
+        When set to YES, display debugging information that includes passphrases used and passphrase related env vars set.
     BORG_EXIT_CODES
         When set to "modern", the borg process will return more specific exit codes (rc).
         When set to "legacy", the borg process will return rc 2 for all errors, 1 for all warnings, 0 for success.

src/borg/helpers/passphrase.py

@@ -143,6 +143,9 @@ class Passphrase(str):
                 {fmt_var("BORG_PASSPHRASE")}
                 {fmt_var("BORG_PASSCOMMAND")}
                 {fmt_var("BORG_PASSPHRASE_FD")}
+                {fmt_var("BORG_OTHER_PASSPHRASE")}
+                {fmt_var("BORG_OTHER_PASSCOMMAND")}
+                {fmt_var("BORG_OTHER_PASSPHRASE_FD")}
                 """
             )
             print(passphrase_info, file=sys.stderr)