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.

UnsafeControlPath

Warns when ControlPath doesn’t include the tokens needed to uniquely identify connections. The OpenSSH man page recommends that ControlPath include at least %h, %p, and %r (or alternatively %C).

WildcardHostOrder

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