Why does the ATO have "unclaimed super", should I do something about it?

I am an Australian Citizen currently living in the UK.
I logged on to the Australian Tax Office (ATO) website today an the ATO tells me i have unclaimed super.
It’s about $3000, and is exactly equal to the amount of super I had in my fund when i left Australia.
It was basically just contributions I made working as a teenager and during university, I have much more now in my UK pension fund.

As far as I can tell, this means my superannuation fund has closed my account and all the money is now being held by the tax office.
I am not sure why, but I suspect it was because of one or more of:

• I am not a resident in Australia,
• They couldn’t contact me
• It was a small amount of money
• I wasn’t making contributions

So I think now the ATO has the money?

Do I need to do anything about it?, Can I do anything about it?

Will it continue to gain interest while the ATO has it?
My superfund had actually been doing pretty well at it over the last few years, net 5-10% growth per year. (Incontrast to my old superfund, which made 0.1% then changed me fees that far exceeded that).
I would rather not have it sitting there as inflation devalues it down to nothing.

I don’t have any desire to try and remove money from my superfund, I am many decades away from retiring and assume i will probably move back to Australia before I do.