Is it prohibited to wear tefillin on Chol HaMoed (the intermediate days of Pesach and Sukkot)?

Synopsis

A major dispute between Sephardic and Ashkenazic practice. The Mechaber prohibits tefillin on Chol HaMoed because it too is an אות. The Rema records the Ashkenazic custom to wear them (with a blessing said quietly). Later authorities debated whether any blessing should be recited.

Rishonim
Early Acharonim
Late Acharonim
Lenient
Strict
Lesser cited
Major authority

Discussion

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