This was discussed on the koha-devel list, and I finally sent some patches for this. I just open the bug so we can track the status of it.
Created attachment 2697 [details] [review] Enable MARC documentation
Started work testing and improving the patch. Current issues: * links to MARC21 fields <= 099 broken * patch breaks field cloning
Created attachment 2713 [details] [review] follow-up patch with improvements
Patches pushed, please test and close
This bug is mentioned in: bug 5190: link to MARC21/UNIMARC online doc in the bib editor http://lists.koha-community.org/pipermail/koha-patches/2010-October/012766.html bug 5190: improve linking to MARC field documentation http://lists.koha-community.org/pipermail/koha-patches/2010-October/012767.html
This bug has a patch presently committed to HEAD and 3.2.x. Please take the appropriate action to update the status of this bug. Remember, bugs which have been resolved should be tested and marked closed, preferably by the original reporter.
A fix for this bug has been committed to the current development HEAD as well as released in 3.2.1.