89941354_GnuTLS_3_4_3__Priority_Strings__Description
[Keyword] %COMPAT [Description] 
will enable compatibility mode. It might mean that violations of the protocols are allowed as long as maximum compatibility with problematic clients and servers is achieved. More specifically this string would disable TLS record random padding, tolerate packets over the maximum allowed TLS record, and add a padding to TLS Client Hello packet to prevent it being in the 256-512 range which is known to be causing issues with a commonly used firewall.
GnuTLS 3.4.3: Priority Strings
Description