+
+
+### New files
+
+For pages, capitalize at least the first letter of the filename (GitHub doesn't capitalize titles automatically, GitLab will do what it wants anyway).
+
+Use dashes in page names, not underscores, not spaces - dashes get converted to spaces in page titles so we have a nice title on every page. Using GL's editor will pretend to create pages with spaces but the filenames in fact have dashes so use dashes in links, otherwise the GH mirror will look broken. Some pages might have underscores in names for historical reasons - they already have many outside links (from forums, etc.) pointing to them.
+
+It's ok (and preferred) to put images and other assets into subdirectories but we have to **put pages in root** because GitHub doesn't support subdirs properly (it flattens everything - this can cause collisions, plus there is no way to link from subdir to another subdir that works on both GitLab and GitHub).
+
+
+### Automated checking
+
+Neither GL not GH support red links (highlighting broken links) so there's a script in [`assets/check-and-fix.py`](assets/check-and-fix.py) that finds broken links and unreachable files. To use it, clone the wiki and run the script in its root. It can also automatically move or rename files that don't follow the above guidelines if you run it with `--fix`.