I came from gdb where I can symbolically list the source with l func, and then press enter to learn more about the definition.
l func
How to do it in windbg?
If you want to parse func type u func, if you want to open source type.open -a func
u func
.open -a func
If you want to specify the source in the command window or in cdb, use lsa func
lsa func
you can replace func address.
Just select File-> Open Source File ..