I tried it (the online version, https://asterisklint.osso.pub/) using a production dialplan which is written in AEL, which it does not understand.
After munging ‘dialplan show’ into ‘basic dialplan,’ it reported over 300 errors that are mostly stylistic
E_VAR_BAD_TOKENS: bad tokens in variable name 'CALL-ID'
W_APP_BAD_CASE: app 'agi' does not have the proper Case 'AGI'
W_WSH_BOL: unexpected leading whitespace
It also fails parsing statements like ‘exten = foo,1,…’ because it thinks the ‘>’ is important.
The program appears to ‘know’ all of the Asterisk application names, but not some ‘newer’ ones like:
E_APP_MISSING: app 'MSet' does not exist, dialplan will halt here!
E_APP_MISSING: app 'stopmonitor' does not exist, dialplan will halt here!
It did note a missing closing bracket and a missing closing brace, but did not note a missing closing parenthesis.