For [[Special:NewPages]] there are the parameters &namespace=0 and &username=JohnDoe, and they also do work for the web feeds (RSS/Atom) and are even inherited! Furthermore parameters like &limit=10 also do work there, but are not taken over in the links, sadly. Other parameters like &hideliu=1 seem to do not work at all there (on enwiki, on dewiki &hideliu=1 works for the special page and even for RSS).
For the feeds of [[Special:RecentChanges]] and [[Special:RecentChangesLinked]] &limit=1 works, the most other parameters like &namespace=4 or &hideliu=1 do not. The URL is not inherited at all (always just ^...&feed=rss$).
For revision history pages' feeds even &limit=1 does not work.
- Provide all parameters for all web feeds!
- If a parameter is found in the URL, let the feed links contain it, too!
At the moment it is as inconsistent and cumbersomely as just can be; not very helpful.
Especially for web feed notification - see also bug 5220#c21 - the availability and adoption (URL-to-link) of all those parameters are essential!