Grextras installation

Hi,
I am using gnuradio 3.6.3. I am trying to install precog. So to do
that i have to install gr-extras. But the git repository for gr-extras
says
sorry and nothing else

https://github.com/guruofquality/grextras/blob/master/README.txt

How should i install gr-extras now?

Yeah not sure what’s going on there, no explanation nothing, but it’s
git and the internet … history is always there, even if unlinked :

https://github.com/guruofquality/grextras/tree/08a5747bff911f3c8722224d3d2a4f2f8fa68b10

Cheers,

Sylvain