sRGB (standard Red Green Blue) is an RGB color space that HP and Microsoft created cooperatively in 1996 to use on monitors, printers, and the Internet. It is often the default color space for images.
Even though the monitors are linear the renderers themselves are non linear. GPUs already have hardware support to convert to sRGB while sending output to monitor. Hence we send in data in linear and perform calculations in linear.
From the previous assignments, we need to convert all color values when passing to shaders. Most colors that we use come from other applications which render them in sRGB. So we convert them into linear in our graphics pipeline in C++.
Below are the before and after images of the same scene with and without sRGB: