Purpose of "struct object_entry *oe = oe;"?

Out of curiousity, where did this convention/idiom come from, and what's it for?

I presume it's to remove a warning ("oe might be used uninitialised") on a compiler (or something) that's clever enough to attempt such analysis but too stupid to notice that the supposed initialisation is using something uninitialised (or perhaps the compiler's deliberately recognising the convention?). Is that right, or does it actually do something more?

I'm mostly surprised that it surprises me. Is it used commonly in other projects? (It appears not to be mentioned in CodingGuidelines; should it be?)

(First instance in git that I can see is 67affd5173da059ca60aab7896985331acacd9b4, 2006.)