Module basic 

Structs

DuplicateHost

Warns when multiple Host blocks have the same pattern.

IdentityFileExists

Errors when an IdentityFile points to a file that doesn’t exist. Skips paths containing % or ${ (template variables).

WildcardHostOrder

Warns when Host * appears before more specific Host blocks. In OpenSSH, first match wins, so Host * should usually come last.