Having had tomatoes sprout from compost, I can guess exactly how these tomatoes came to be. Someone dropped a tomato slice, or a whole tomato at some point in the winter or spring. Some seeds germinated when the weather finally warmed up enough for tomato seeds. And they grew.
To tomatoes are very small, which tells me that either someone dropped cherry tomatoes, or the seeds were hybridized, and didn’t grow true.
You will note from the many blossoms wanting to form tomatoes and the relatively few actual tomatoes, and the fact that it is early September, that this climate is not a natural one for the tomato. We have to start them indoors early and then transplant them out. Anything sprouted from seed in the ground won’t be ripe when the weather turns.
These particular tomatoes were gone (tomatoes, plant and all) the next week. I wonder if someone saved the ripe tomatoes, or just weeded the thing into the trash.