It is a javascript library to display RRD files which was created by Frank Wuerthwein and Igor Sfiligoi.
I created only another version for own needs. This version edited rrdFlotMatrix module, which stacks data sources from multiple RRD files in default behavior. This version disables stacking function and displays overlaped DSs.
This version also translates months into czech language and transforms timezone into +1.
I upload my edited code here, because I think it could be useful for someone.