Known. At least three groups painted the same rock over about 9,000 years.
At Kakapel, a rock shelter in western Kenya, the paintings lie in layers. The oldest layer has faded red and white shapes, linked to hunter-gatherer-fisher people. A later layer shows at least 25 cattle with long horns and no humps, linked to later cattle-keeping people. A still later group painted thick white and yellow-white shapes.
The page says the exact meaning of the paintings is still being studied.
https://www.ancient-origins.net/news-history-archaeology/kakapel-rock-art-00102741