DevTools failed to load SourceMap: Could not load content for https://flowoxonline.wpengine.com/de/wp-content/plugins/multilingualpress/public/css/admin.css.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE code example

Example 1: DevTools failed to load SourceMap: Could not load content for

Open Developer Tools, 
go to "Settings" for Developer Tools, 
then uncheck Enable JavaScript Sourcemaps under the "Sources" settings.
Restart Browser if needed

Example 2: DevTools failed to load SourceMap: Could not load content for chrome-extension

DevTools failed to load SourceMap: Could not load content for 
chrome-extension://lhdoppojpmngadmnindnejefpokejbdd/browser-polyfill.js.map