Unaspirated or tenuis consonants are occasionally marked with the modifier letter for unaspiration ⟨◌˭⟩, a superscript equal sign: ⟨t˭⟩. Usually, however, unaspirated consonants are left unmarked: ⟨t⟩.
How are unaspirated or tenuis consonants sometimes marked for unaspiration? What is the superscript equal sign? Most often, unaspirated consonants are what? How are unaspirated consonants left unmarked?