Module basic 

Structs

DeprecatedWeakAlgorithms

DuplicateDirectives

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).

InsecureOption

Warns about directives that weaken SSH security.

WildcardHostOrder

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