That all depends on the specific source of the "raw" images.

"Raw" isn't a file format, or even a type of file. It's just a catchphrase we use to refer to image information recorded at the most basic level by a camera.

Since different cameras can and often will do things differently, exactly what a raw file contains and does not contain can vary from one camera to the next. Manufacturers tend to do most or all of the same things in the various models they offer, but there's a significant variation about what is and is not processed before raw information is recorded from one camera maker to the next.

Most raw image files from cameras with Bayer mask color arrays are saved without any demosaicing or gamma correction applied. So each "pixel" contains a single, linear, monochromatic luminance value that tells how much light energy was recorded by each photosite on the sensor.

• Almost all do statistical noise reduction prior to analog-to-digital conversion.
• Some do little else, other than basic noise reduction, before converting the analog signal to digital information and recording the values at that point.
• Other do things as extensive as lens correction for things such as distortion and vignetting, and maybe even chromatic aberration, before saving the file.

For more about what information raw image files tend to contain, please see these related questions and their answers here at Photo.SE:

RAW files store 3 colors per pixel, or only one?
What does an unprocessed RAW file look like?
Why don't mainstream sensors use CYM filters instead of RGB?
Why can software correct white balance more accurately for RAW files than it can with JPEGs?
RAW in ACR vs JPG in ACR
What is RAW, technically?