I'm not sure if these are reported or if this is the correct spot, but the homepage listed in app-emacs/folding appears to be no more. I did a quick browse and nothing stood out as being a replacement so maybe someone else can suggest one. Reproducible: Always Steps to Reproduce: 1. 2. 3.
I updated the ebuild to use http://www.emacswiki.org/cgi-bin/wiki/FoldingMode as the HOMEPAGE. There are some docs there and notes about the lack of home page. Thanks for the bug report.