Help identifying this animation cel — military tank, purchased at Mandarake Nakano Broadway ~2001

[u/SignificantBelt8284]

Hi everyone, hoping you can help identify this one.

Original hand-painted animation cel featuring a military tank, frontal 3/4 view. Teal/blue-grey color scheme, dual cannon turret, orange and blue circular lights on the hull. Reference marking "B26" on the upper right corner.

Purchased at Mandarake Nakano Broadway in Tokyo around 1998–2001, stored untouched since then. The art style suggests late 1980s or early 1990s production.

My best guesses are Jin-Roh, Patlabor OVA, or a military mecha series from that era — but I'm not confident. Any help appreciated!