The Cap / Pcap file format is the most common capture format for Wireshark.
Additional information on this file format can be found in :
https://gitlab.com/wireshark/wireshark/-/wikis/Development/LibpcapFileFormat
https://en.wikipedia.org/wiki/Pcap
Also the newer PcapNg (PCAP Next Generation) capture format for Wireshark is supported.
Additional information on this file format can be found in :
https://gitlab.com/wireshark/wireshark/-/wikis/Development/PcapNg