I am seeing that as basically defensive coding. Similar to how you may do this:
switch (mode) {
case FOO: ... break;
case BAR: ... break;
}
Do you need the very last break? Technically no, but including it so that you don't forget it when you need it later can be a good idea.
(Also, I think explicitly using comparison operators in conditionals might be the idiomatic thing to do in Go. Someone correct me here if I'm wrong about that.)
Oops, did everything in decimal. Good point and correction. Still, the difference in legibility and implications of the two lines of code are important. Modern compilers would optimize ((foo & 0x80) == 0x80) to (foo & 0x80) but leave ((foo & 0x60) == 0x60) alone because it is testing more than one bit.
