I believe in the old IDE, the data type "byte" changed color to blue. In the current IDE beta.5, it does not appear to do so. I am on macOS Big Sur.

The colors have no significance, and the compiler is color-blind.
That's right. The colors have no significance to the complier.
The colors are aides to the developer however. That's why I made this post.
Thanks for your report @M_James_O. This is being tracked by the Arduino IDE developers here: