How to keep using adblockers on chrome and chromium

1. google's manifest v3 has no analouge to the webRequestBlocking API, which is neccesary for (effective) adblockers to work
2. starting in chrome version 127, the transition to mv3 will start cutting off the use of mv2 extensions alltogether
3. this will inevitably piss of enterprises when their extensions don't work, so the ExtensionManifestV2Availability key was added and will presumably stay forever after enterprises complain enough

You can use this as a regular user, which will let you keep your mv2 extensions even after they're supposed to stop working

Linux

In a terminal, run:

sudo mkdir -p /etc/opt/chrome/policies/managed /etc/opt/chromium/policies/managed
echo '{ "ExtensionManifestV2Availability": 2 }' | sudo tee /etc/opt/chrome/policies/managed/policy.json /etc/opt/chromium/policies/managed/policy.json

ChromeOS

• enable developer mode
• upon rebooting, go into vt2 (shift+ctrl+right arrow function key)
• log in as root
• type in /usr/libexec/debugd/helpers/dev_features_rootfs_verification && reboot
• upon rebooting, go into vt2 again and log in as root
• run the commands from the linux section

Windows

Open regedit, and create Software\Policies\Google\Chrome\ExtensionManifestV2Availability as a dword set to 0x00000002

MacOS

In a terminal, run: defaults write com.google.Chrome ExtensionManifestV2Availability 2

(note that i haven't tested this for mac. please let me know if it doesn't work)