HTMLtidy or tidy

Koha uses HTML::Template with uses some new html tags that make tidy error

you can easilty create an ~/.tidyrc file containing this to tell tidy what to do with HTML::Template tags it finds in your *.tmpl file

 new-blocklevel-tags: tmpl_loop tmpl_if tmpl_else tmpl_unless 
 new-inline-tags: tmpl_var tmpl_include
 indent: auto
 indent-spaces: 1
 vertical-space: n
 wrap: 0

then run

 tidy -m ./foo.tmpl

and prepare to be beautified!