A Chrome extension that captures the content of postMessage.
Tried this in Jan 2023 to understand how the youtube javascript embed API interacts over postMessage. This extension doesn't catch or report any of the postMessages that may happen in sub-iframes (e.g. not in the top window). So if you prototype something in codepen or whatever you won't see the postMessages in this extension. It appears (limited testing) it only reports postMessages RECEIVED by the top window...so you don't even see postMessages sent by the top window to child iframes. This makes this extension pretty useless as you can add a single "message" listener that logs messages in the devtools console to accomplish the same thing.
wille.eklund
https://shodan.io
inisomniac1426
Lukas Weichselbaum
https://tweak-extension.com
davtur19
dylan
alxHenry Developer
Ludovic COULON & Riadh BOUCHAHOUA
kevin_mizu
yishiashia
Phil Grayson