yeah, it’s not so straightforward to find them - it’s implemented as a single-file library, so the shader code is embedded in the C code - you can find it here https://github.com/mattiasgustavsson/crtview/blob/de7897958ac1f346ca7fa3dbf5a57dab5fcc5bb3/source/crtemu_pc.h#L57
It’s a little more complicated than just a shader though - I use a couple of extra passes and buffers, to do a good gaussian blur with decent performance, and to accumulate pixel values over time, so there can be a visible blur trail when objects move. I don’t know how tricky it would be to recreate that for OBS...
I do have an earlier version of the shader here:
https://www.shadertoy.com/view/Ms23DR
It doesn’t use the extra buffers, it is just a plain pixel shader. So it does not have the blur trail, and it is also very GPU intensive due to the gaussian blur being done on the full resolution rather than on a smaller buffer.