Honestly, it seems like a faddish buzzword, incorrectly used.
IIRC "decolonizing" sometimes means returning cultural artifacts acquired during colonial times to the regions/cultures where they originated. However, it doesn't make any sense to do that to cultural artifacts created by citizens a colonial power in their own originating culture. Honestly, that sounds like another kind of colonization.
This article seems like a mess trying to force a combination of trendy ideology with personal experience that don't really fit. For instance:
> For her, the archive became a place of postcolonial recovery and remembering.
What's that in reference too? A student seeing a card catalog that's still in use, and being reminded of personally using them in the past. It's weirdly trying to particularize the universal. I'm about the farthest from a "colonized" person there is, but I could have had the exact same reaction to the exact same situation as that student. The only difference is that I have the wrong background, so no one's going to try to gratuitously describe my reaction as something "postcolonial."