Subjective.
“The /e/ ROM is a fork of Android and in particular the LineageOS flavor of Android.”
(https://doc.e.foundation/what-s-e)
“/e/ is forked from LineageOS.”
(https://doc.e.foundation/support-topics/about-e#is-e-a-combination-of-lineageos-and-microg)
What is the “it” you are referring to?
“Is /e/ open source? Yes - all source code is available on our /e/ Gitlab. You can compile or fork it. Some prebuilt applications are used in the system. They are built separately from source code available here or synced from open source repositories such as F-Droid. We ship one proprietary application though (read the statement).”
(https://doc.e.foundation/support-topics/about-e#is-e-open-source)
https://doc.e.foundation/support-topics/about-e#is-e-a-combination-of-lineageos-and-microg
https://doc.e.foundation/what-s-e → https://e.foundation/wp-content/uploads/2020/09/e-state-of-degooglisation.pdf
You’d better not let me choose a side
.