urls.map is a collection of patterns against which incoming HTTP requests are matched to dispatch those requests to the correct code. If you are familiar with Ruby on Rails it is similar to the routes file.

TiddlyWeb includes a default urls.map that has extensive comments explaining each mapping. You can see that file.

You may replace the entire urls.map with a different one by setting urls_map in tiddlywebconfig.py.

You may add to the urls.map or change how an existing mapping is handled with plugins.