WGL - ChoosePixelFormat and sRGB framebuffer

I have a legacy OpenGL application which sets a pixel format based of ChoosePixelFormat instead of wglChoosePixelFormatARB or wglGetPixelFormatAttribivARB/wglGetPixelFormatAttribfvARB. ChoosePixelFormat doesn’t allow to set a framebuffer color space explicitly using WGL_EXT_colorspace Despite that I have noticed that calling glEnable(GL_FRAMEBUFFER_SRB) provides a color space conversion when render a test texture. How does it work ? Does ChoosePixelFormat set sRGB colorspace by default ?

Physical framebuffers always use some form of gamma law; that’s just how video standards work (NTSC, VGA, HDMI, …, all of them). Enabling GL_FRAMEBUFFER_SRGB just tells OpenGL to stop pretending that it’s linear.