I think that allowing users to define manual Launchbox configurations would be useful: this way we could have a default file for the project to launch (in most cases index.php) and the chance to "override" this setting and run a specified file, without having to edit project properties every time.

Hmm. If I got you right...
Indeed, in case if index.php dispatches all calls, there is very little chose beyound setting "Default file to run". What's about two features below that are already available?
-Run History > see popups right to all "run" buttons, namely Run (Ctrl+F9), Run in debugger (F9), Run profiler (Alt-F9)
-Run->Repeat last run
I think they may help run the same scripts again and again without setting only one in "default to run" in the project.

Anyway, I agree, "Add" in the Launchbox popup would he helpful.

Yes, but one may have needs to run different files rather than the default one... It's good to see you agree

Any news on this? Even "Run this file" and "Debug this file", which overrides the default file, could be useful...

All non-trivial changes in the functionality can be done only in new versions.

When working with many php frameworks there is one single entry point (usually index.php) as already mentioned. So often you need to supply steering info in the query string such as controller and task. This would be where I would find the ability to manually add ,or possibly even better, clone a big help. Clone would allow you to quickly replicate an existing entry where all that is required is a small change to an existing shortcut to create the new shortcut. I noticed this thread has been dormant for a long time, but has had a lot of views. Wouldn't it help if these feature requests were created as polls so that you could easily see which ones have had the largest number of votes?