Can't make changes to Soundfont_X.xml files without editing the extracted folder

There's currently no way to add SFXs without editing the extracted folder because you can't edit the Soundfont_X.xml files otherwise. Copying them to the regular assets folder and editing that produces this error:

Start by reproducing the error when a Soundfont_X.xml file is copied into the regular assets folder, then trace how the extracted folder and asset files are handled. Identify the asset-loading or build entry point involved; done means Soundfont_X.xml files can be edited in the regular assets folder to add SFXs without the reported error.

Written by the indexing model from the issue text.