Download Chromium from https://chromium.woolyss.com/

Windows
  unzip and rezip

OSX
    download on a Windows machine up-to-date, all-codecs, no-sync  (check the link is actually to ...nosync.zip)
    if you download on OSX you will pick up the 'not trusted download, can't open' problem
    rename to browser-osx64-...zip  - if you repack it then it will fail to run
    copy to OSX and verify that
        open -W ...zip
        open Chromium.app
    actually works
    build plugin
    
Linux

https://ungoogled-software.github.io/ungoogled-chromium-binaries/

Portable Linux 64-bit  ( -> https://www.opendesktop.org/p/1265177/ )

    unzip and rezip
    
    
WebRTC
    
    https://repo.maven.apache.org/maven2/dev/onvoid/webrtc/webrtc-java/