Eastman 2374 - Panchromatic Sound Recording Film 2374 (ESTAR) - "...is a high contrast, panchromatic black-and-white film designed for recording variable-area sound track negatives with a tungsten light source, and/or producing  digital sound track negatives."  Now, if this film sounds strange, it is.  Sound tracks are superimposed on the movie footage to make the final prints. After processing, the words "KODAK Safety Film", the strip number, and year symbol are located in the center, along the length of the film. This is repeated every 3-5 frames.  So, the cool thing or the infuriating thing is that you would see this in some of your full-frame images. After all, this wasn't designed as a pictorial film.
Pictorial use - This film is contrasty, which makes sense for a soundtrack.  There's also the imprinting of the code down the center every few frames.  It is fine-grained, and the working ISO is 25-50.  D-96 is a good developer, at about 6 minutes.
Additional  Recommended processing times at ISO 50

D-76 Stock - 6 minutes @68 degrees

HC-110 - Dilution H - 7.5  minutes @ 68 degrees (Dilution B, not recommended for ISO 50)

Xtol stock - 5 minutes @ 68 minutes
FPP Super Monobath - ISO  25, 85 degrees, 3.5 minutes.
Photographer’s Formulary TD3, @ 24 minutes, minor base fog.

If shooting at ISO 100
HC-110 - Dilution H, 8.5 minutes, 68 degrees