Hi The situation has improved a lot with the VCS cache and changes in the makefiles (thanks Steve!).
Here are logs of a recent build after a change in the footer (hence, rebuilding most of the pages): https://www-master.debian.org/build-logs/webwml/often.change_in_footer.log 4webwml took 8h 30 min approx. Here is the detailed log: https://www-master.debian.org/build-logs/webwml/wml_run.change_in_footer.log (with CVS such builds took more than 24h). While I know there is still room for improvement, I think the current status of things is acceptable, so I propose to close the bug. Cheers -- Laura Arjona Reina https://wiki.debian.org/LauraArjona
