Trace files (captured data) from Wireshark are already in text format, so in this sense, there is no reason to export these to plain text. What is often done, though, is export to a structured text format, such as CSV, or to a text-based ASCII/XML format. All of this can be done with Wireshark. We do not know about any dedicated converter for .trace files at this moment.
Updated: January 23, 2024