It is important to know that we have no secret information. It comes through the large-scale analysis of open-source information that comes primarily from, in this case, social media parents looking for their kids, combined with the data being released through bad tradecraft by the Russians, combined with the fact that they are not hiding it.
This is primarily a propaganda operation. They are attempting to rebrand a failing invasion. In so doing, they are providing us with the ability to extract a map from their social media, which allows us to use things like satellites to then monitor patterns of life, including logistical patterns.
What we have here is the fusion, the mosaic effect, of multiple streams together.