sngrep(8) on Linux
The text de74b07c3e8b, as Debian 10 (Buster) shipped it.
SIP Messages flow viewer
Flags it lists
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-H -
-I -
-L -
-N -
-O -
-R -
-V -
-c -
-d -
-h -
-i -
-k -
-l -
-q -
-v