There is a Save as option through a right click on a package. You shouldn't rename sbs files manually as it could potentially lead to broken dependencies.
you don't need to rename the file - just select xml from the language menu ctrl+shift+alt+b should format the file with line breaks / indents so it's readable too (not 100% reliable) aliases work fine though - our substance library has been through 7 years, 6 projects and 10 material artists without any difficult…