Understood, that's clear. Thanks, Martin.

You can run synchronize twice. Once with -filemask and once with -delete and Interface\SynchronizeParams=4 (= Existing files only – to prevent uploading files you do not want to upload). You cannot change SynchronizeParams in-process though. So you need to run even WinSCP twice for that.
https://winscp.net/eng/docs/rawconfig#interface_synchronizeparams

Hello

I'm using a script to sync that contains

I see that -filemask also applies to the -delete option, so if I have, for example, an .exe on the destination, it won't delete it (I assume it doesn't exist on the source). Is there a way to make -filemask not affect -delete?

Thanks