hi all experts,

i noticed that when i mine with ethermine pool, there is:
1) DevFee: ETH: Stratum - Connected (eu1.ethermine.org:14444)
2) DevFee: start mining
3) DevFee: ETH: checking pool connection...
4) DevFee: stop mining and disconnect

What does the devfee above means?
But when i mine alpereum for past 12 days, there is no "devfee" in any of the log.

could some one enlighten me?

thank you.

by the way, i am using windows 10 with 1 GPU 7950 only.