pcre2_match_context_free man page
PCRE2 — Perl-compatible regular expressions (revised API)
void pcre2_match_context_free(pcre2_match_context *mcontext);
This function frees the memory occupied by a match context, using the memory freeing function from the general context with which it was created, or free() if that was not set.
There is a complete description of the PCRE2 native API in the pcre2api page and a description of the POSIX API in the pcre2posix page.