Chicken wire mesh on Sherman Firefly turret.....

[Jakko Westerbeke]

I agree with David’s assessment: it wouldn’t cover anything important, like hatches, periscopes, etc., and as for how it’s attached … that’s really anyone’s guess, unless you can find a better photo that shows it in close-up (which is rather unlikely — none of the people taking these photos seem to have been modellers, oddly enough ).