Here is a list of all modules:
[detail level 12]
oData Channel Compression moduleThis module offers compression of data channel packets
oControl Channel Processor moduleThis module controls the setup and maintenance of VPN tunnels and the associated security parameters
oControl Channel TLS moduleThis module provides secure encapsulation of control channel messages exchanged between OpenVPN peers
|\Control channel encryption (--tls-crypt)
oData Channel Control moduleThis module controls the processing of packets as they pass through the data channel
oMain Event Loop moduleThis main event loop module drives the packet processing of OpenVPN
oData Channel Fragmentation moduleThe Data Channel Fragmentation module offers fragmentation of data channel packets
oReliability Layer moduleThe Reliability Layer is part of OpenVPN's control channel
oData Channel Crypto moduleThe Data Channel Crypto Module performs cryptographic operations on data channel packets
oExternal Multiplexer moduleThe External Multiplexer is the link between the external network interface and the other OpenVPN modules
\Internal Multiplexer moduleThe Internal Multiplexer is the link between the virtual tun/tap network interface and the Data Channel Control module