- pkedcjkdefgpdelpbcmbmeomcjbeemfm is the Chrome Media Router, without it, you can go to chrome://flags and Enable the #load-media-router-component-extension as much as you want, no chromecast device will ever be detected.
1: copy pkedcjkdefgpdelpbcmbmeomcjbeemfm folder from a google-chrome profile ( ~/.config/google-chrome/Default/Extensions/pkedcjkdefgpdelpbcmbmeomcjbeemfm) to the chromium profile ~/.config/chromium/Default/Extensions/pkedcjkdefgpdelpbcmbmeomcjbeemfm
( If you copy from a windows installation, make sure the files are chmod 600, the folders are 700 and you are the right owner)
2: in Chromium, go to chrome://extensions/, enable "Developer Mode", then "Load Unpacked" and point to ~/.config/chromium/Default/Extensions/pkedcjkdefgpdelpbcmbmeomcjbeemfm
3: Now Chrome Media Router is loaded and the chromecast devices will be detected: