Right-click in the Name column, select "Save all as HAR with content". Then grep for the headers, e.g.,

   sed -n '/headers\":/,/\]/p' example.com.har

While running Chrome, try

   ps ax |grep -o field-trial-handle[^\ ]*[0-9]

Handle to the shared memory segment containing field trial state that is to be shared between processes. The argument to this switch is the handle id (pointer on Windows) as a string, followed by a comma, then the size of the shared memory segment as a string.

Also, can try typing "chrome://versions" in the address bar

https://superuser.com/questions/541466/what-is-the-variation...

https://www.ghacks.net/2013/04/05/field-trials-in-chrome-how...

Further reading:

https://chromium.googlesource.com/chromium/src/+/master/comp...

https://chromium.googlesource.com/chromium/src/+/master/comp...