I'm looking for a utility that can check for broken links to external
In the FM docs themselves or in your output?
Ideally in the FM file. Check/validate links to external URLs and generate a 'bad links' report with the link location and problem URL. If that's not possible, we could run a check on the PDF output, but we'd have to go back to Frame to fix the links and then re-generate the PDF. I know there are plug-ins for PDF, but I haven't found a free one. Same issues if I save as RTF and run the link validation through Word.
Sounds like something that would require scripting - would you like me to move this post over there?