Part of our template title normalization was forcing all titles to lowercase, but wiki titles are case-sensitive. This means that a template "GPL" would have matched "gpl", when they may be different articles. The correct normalization is "ucfirst", making the first character uppercase but leaving the rest of the title unchanged. The impact of this change should be minimal, but the lowercase assumption is built into much of our code.
I noticed this as part of work for T228858.
which is soft-blocked by this detail.