Debugging Ports
Enabling Debugging During Build
Refer to ports(7).
Checking Debugging Symbols
After a port has been built with the above debugging steps, you can check they have worked by using file(1) to analyze the installed binaries.
$ file /usr/local/sbin/dovecot /usr/local/sbin/dovecot: ELF 64-bit LSB executable, x86-64, version 1 (FreeBSD), dynamically linked, interpreter /libexec/ld-elf.so.1, for FreeBSD 12.0 (1200054), FreeBSD-style, with debug_info, not stripped
Note that this file has debug_info and is not stripped.