I like to move modified configs to a dedicated folder, to see immediately all config related changes.
Most of the time this is done through configsource and / or transformations.
Is there a way to do this with forms.config?
Unfortunately no. Class responsible for reading configuration (`EPiServer.Forms.Configuration.EPiServerFormsSection`) is asking Shell module table to resolve path to "Forms.config" file. Meaning that file path will be translated to directory under "/modules/_protected/...".
Might be feature request for EPiServer.