Does @ at sign used for tother than decorators?

[buran]

Do I see it is calling previously defined decorator function called triton.autotune?

Did you check the docs?

It's a decorator with arguments and the decorated function is somewhere down in the code you look at (i.e. you didn't show that part here)

In the example in the docs the function kernel() is decorated with 2 decorators - @triton.autotune and @triton.jit