I am not sure we have enough information to say what is being claimed. Flag planting is claiming facts and discoveries(in science) or land. There are likely other things that can be claimed and would be described with this term. Do either of these fit?

Flag planting means "claiming ownership" of something. It is a western custom or unspoken rule that when "terra nillius" (no man's land) is found, whichever country lay its claim on the land is by putting their flag on the soil. For example, when the American Continent was discovered, Spain would plant the Spanish flag on the land (near the beach) to claim it for their sovereign. When the US landed on the moon, the US flag was planted on the moon but laid its claim for all mankind so that the moon is considered to be owned by Earth and not just the US. I doubt any other country would do that. Just look at the South Pole as an example.