Green netting under the grass

[Gotthetshirt23]

Hello
Bought out new home at the end of last year , seems old owners were very keen gardeners but liked privacy type bushes and hedgerow and left things grow unchecked .
There is a small patch of grass and I've been trying to weed and preserve it , it seems there is a layer of plastic net under the grass , only a few cms and is pulling up as I pull up nettles , mint and foxgloves.
Why would this be used in these circs ? I'm baffled ?

Generally it’s done if it’s an area where it’s hard to grow grass as it can help to protect the seed until it germinates.

Or to stop cats digging up and using it as a loo?

Thank you -
It's the whole lawn area ? Not massive though .

Our garden has that. I assumed it was part of the turf when it was laid, our house is on a modern estate.