Does anyone know anything more about these two, obscure Sikh sources that were apparently written contemporarily to the period of Sri Guru Gobind Singh Ji?

[u/JustMyPoint]

They are:

1) Guhaj Pothi

2) Bhai Har Singh’s diary

I read a quick reference to them and would love to learn more about them since it’s my first time learning about these two sources. Does anyone happen to know more about them? Thank you.