Flap in cats stomach.

Here is a stray kitten in my neighborhood that ive been trying to catch . I did today and ive noticed she had kittens.

Her teets are a little saggy but she is dried up so I assume the kittens are already old. I havent seen any kittens yet.

Ive notice something wrong on her left side.
Her one Teet is a little swolen and a little hard and there is a flap like thing on her stomach but underneath the skin. You cant see it but you can feel it.

It feels like a little silicone flap. Its about 10cm long and I can put my hand a little underneath it.
She doesnt seem to be in pain when I touch it and she also doesnt try to get away.

Any idea what this might be?
Will be taking her to the vet soon

Does it bulge? Could it be an umbilical hernia?

No it does not bulge. It isnt noticable. You wont even know it is there. It is by the last teets at the bottom.Its a little soft feels like silicone

. you can see it at the bottom. I turned it a little.. When its flat you wont be able to see it

Google said it might be a tumor. And you can also see the one teet is a little swolen

it goes until right under the top teet but alot smaller at the top.. Like a pear shape

Haven't a clue. You're taking her to the vet so let us know. Get her fixed too!

Had a hard time catching her but she will get fixed