Where is the code that reads the XSD file?

[Rafael Sousa (Ext_Altior)]

Hi everybody!
 
In what file/class is the schema file .xsd being read from disk?
 
I've been digging down the source code to find this, but it hasn't been easy... 
If any of you already knows it, it will save me some time.
 
Thanks in advance,
 
Rafael Sousa