Debug Symbols and PE

I wanted to better understand how debug symbols work in relation with the PE.

As I understand the pdb file holds symbol information on its PE. But how exactly can a debugger take a PE and its pdb file and display code?

For instance:

• What information can be stored in the pdb file that will link to the symbols of the PE
• How does a debugger know to transform an optimized for loop in binary to a for loop in code?

Thanks!

Found the following very helpful resource:
https://www.atmosera.com/blog/pdb-files-what-every-developer-must-know/