"basename" is more common [ci skip]

l3build.dtx

@@ -474,7 +474,7 @@
 %
 % \begin{buildcmd}{doc \meta{name(s)}}
 %   Typesets only the files with the \meta{name(s)} given, which should be the
-%   root name without any extension.
+%   basename without any extension.
 % \end{buildcmd}
 %
 % \begin{buildcmd}{install}