The HTML Corrector module replaces the < bracket with a < when it is the start of an HTML comment. There are two cases where this is a problem:
- Users have fill HTML access and you want to be able to catch missing tags. Users need to be able to copy in content from an older site which contains HTML comments, or the users want to be able to put in comments for their own use.
- At least one module I maintain (Table of Contents) and possibly others use HTML comments as markup so if the module is disabled nothing is rendered to the user. This worked fine in D5, but if the HTML corrector module is enabled then the markup is rendered.
If this is considered to a valid issue, then let me know and I'll create a patch to fix it. Otherwise, please suggest ways around this!