Depends on the version of the editor you're using, I mean by this point there are even custom ones, but in general in ued2 its selecting the package in the class browser then select export from that package(via the context drop down menu just explore that), if its ued1 or whatever then its either export changed scripts (that were changed past original compile from scratch), or export all scripts, which means it will also export things you don't need currently such as the regular default packages etc.