Because this function was not working as you probably think. And in fact it was totally deprecated.
In normal use you don’t have to care. Your image must be in single channel CFA mode.
If not, and you did not check debayer, it is too late. That means your images are already debayered. Probably during capture.
Okay tutorials doesn’t use debayer for bias, but okay. So i need conversion with debayer for bias frames? And after that stack all to build master bias?
Please do you have any great tutorial how to create bias frames and calibrate light frames with bias in Siril? I still don’t know what’s wrong on my side and I want to see someone who actually know how to do it.