I shared "missing videos" yesterday but these weren't missing, at all. I apologize for any inconvenience.
I found out the videos in OP are categorized by the program that was used to make them. My mistake was in assuming "Blender" refers to the raw Blender files of a particular project, as these are sometimes also shared here. There is also a huge overlap in time between the three categories, further contributing to my confusion. I'm not sure what the reason for this categorization is, and I don't mind, per se. But I think it would be useful if it was more clear in the OP what the categories mean.