Related commit 
https://github.com/aibasel/downward/commit/5bfc7c87e10c28357c6ad920c21c85e34681b6e8

(just to reduce the number of future clicks)

Pushed.

On the Discord server (channel #general, 2026-04-10), there was a request to separate the argument parser construction from argument parsing in the translator, so that users of the translator other than Fast Downward itself can hook into the process to add their own parser arguments, or more generally get better control of the argument parsing process.

The change is so simple that I don't expect it to be controversial, so I'll go ahead and make it without a pull request and discussion. If you are unhappy about the change, we can of course undo the change and discuss the topic further.