Recently, I've seen the term “OSE build” a few times for software.
The most recent example is on this page for Swiss File Knife:
Note the term “OSE build” is used for only one of the items listed:
sfk.exe Swiss File Knife for Windows (32/64 bits).
sfk-x64.exe SFK x64 for 64 bit Windows only **(OSE build)**.
sfk-winxp.exe SFK 32 bits for Windows XP systems.
sfk-linux-64.exe SFK for 64 bits Intel Linux, like Ubuntu 64.
sfk-mac-64.exe SFK for current Intel based Macs.
sfk-arm.exe SFK for ARM systems like Raspberry Pi.
sfktray-set-up.exe The SFKTray Status Display Tool for Windows,
Freeware edition, for use with sfk status.
What does this mean?
Performing some searching yielded the possibility of “Open Source Edition”, but all the software projects on that page are open source, so it doesn't seem like it would make sense to label only one of them as an “Open Source Edition?” I'm thinking it’s more likely it means something else.