C<tag>
+Returns an identifier for the mod object.
+It is used to gather mods together when calling C<cover> on them.
+
=item *
-C<cover>
+C<cover $mod>
+
+Returns true if and only if the effects of the mod C<$mod> are already ensured by the current mod object, in which case no actual TikZ code will be emitted for C<$mod>.
+Both mod objects are guaranteed to have the same C<tag>.
=item *
-C<declare>
+C<declare $formatter>
+
+Returns an array reference of TikZ code lines required to declare this mod before using it, formatted by the L<LaTeX::TikZ::Formatter> object C<$formatter> ; or C<undef> if no declarations are needed for this mod.
=item *
-C<apply>
+C<apply $formatter>
+
+Returns the TikZ code that activates the current mod as a string formatted by the L<LaTeX::TikZ::Formatter> object C<$formatter>.
=back