How to fix "DevTools failed to load source map" error?
Simply ignore it because it's not an error!
This is just a warning and the files that are reported missing, are excluded from the Depicter plugin on purpose.
The " .map" files are only intended for modern browsers for more in-depth code inspection and are completely optional for functional plugins. It's a best practice to exclude these files from the final plugin to reduce the file load request and help improve optimizations.
These warnings are safe and will not cause any kind of problems on your website.
Please note that there is a difference between an error and a warning. In fact, you can filter these from your browser console to identify the problematic messages.