question about Equation of Equinoxes

[ncc1701d]

hello,
when calculating the correction "Equation of Equinoxes" refered to as "eqeq"
where
ΔΨ is the Nuations in Longitude

the formula is
eqeq = ΔΨ * cos(e)


Is "e" in this formula the "mean" obliquity of ecliptic(E0) or "true" obliquity of ecliptic ? or can you use either to find eqeq?

thank you.