What is this object?

[pandora206]

This may or may not be housekeeping related. I found this object - foam about 10 x 6 x 2 cm - on my doorstep. I have no idea what it is and as it states 'do not throw away' in capitals, I thought I should find out. An image search could not identify it. Can anyone help please?

google says:

Thanks @Edenmum2. You've done better than me finding out the answer! I don't have a motorhome or caravan, nor do any of my neighbours, so I can safely throw this away.

Could it be something to do with a condensing gas central heating boiler? There's a small pipe on ours that releases excess dribbles outside, and it has frozen solid more than once in the past. The boiler then stops working until we've defrosted it.

Could it be for a water meter? Mine is in my front path and has a circular bit of foam over the dials. I think it’s mainly to keep the spiders warm, which is nice of the water company IMO.