"Chop Wood Carry Water" is metaphor for doing the hard and non-glamorous work. Open source projects can have a lot of this work. Especially those that are popular and have a community.
The image below is a snapshot from the DevStats developer contributions for Helm. Reinhard Nägele, seen here by his GitHub handle of unguiculus, is in the top spot by a wide margin. He got there by chopping a lot of wood and carrying a lot of water.
Reinhard, if you're reading this, I hope you know how much we appreciate all that you've done and continue to do.