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Are they free?
If it is free, will the files be persistent in those IPFS nodes? What if they triggered a GC?
If not free, who paid?
Sorry, maybe a silly question, just new to IPFS.
Thanks for your time, and nice work!

I am quite curious in this part.. How is this implemented in your source code specifically? I can't find where the "several ipfs nodes" come from in the source.
And what benefits bring to them if they provide free storage?
Just couldn't believe there is free lunch..