CMB polarization formula in CAMB

[Yo Toda]

Hi,
Does anyone know how the CMB polarization formula (Delta_{P, l}) is implemented in "equation.f90" file in CAMB?

I'd like to reproduce the EB power spectrum assuming cosmic birefringence using CAMB
(like [https://arxiv.org/pdf/2203.08560]).

I’d greatly appreciate any help or advice.
Thank you for your attention and future advice.

[Antony Lewis]

The CAMB notes describe the equations implemented for the polarization hierarchies (see https://camb.readthedocs.io/en/latest/modifying_code.html which has link)