Originally www/squid-devel was created by me to track squid 4.0 prerelease branch. We have www/squid which is release branch of 4th branch now. So www/squid-devel is meaningful. Please retire it.
A commit references this bug: Author: pizzamig Date: Thu Apr 18 13:53:14 UTC 2019 New revision: 499263 URL: https://svnweb.freebsd.org/changeset/ports/499263 Log: www/squid-devel: Remove port no longer necessary PR: 237359 Submitted by: timp87@gmail.com (maintainer) Changes: head/MOVED head/www/Makefile head/www/squid-devel/
Removed, thanks!