UVM_source file

in uvm why all source file extension use.svh why not .sv extension use.?

In reply to Henriques:

This is a reminder to the reader that this file is
`include
d by another file, and not placed on the compilation command line.

Most tools only recognize *.v and *.sv for Verilog and SystemVerilog source text on the command line. A file with *.svh on the command line would not be recognized as SystemVerilog. An
`include
file is always treated in the same language as the file that
`include
d it.

In reply to dave_59:

Thanks Dave.