In theory it's a competitor to Slipstream. In practice though Libre Relay simply can't relay all consensus valid transactions because there are real technical rationales for almost all the filters in Core.

For example, Slipstream has been used for extremely large transactions. The current Core codebase simply do good transaction selection if the maximum transaction size is close to the block size limit. 

 BTW, I'm fundraising for the next release of Libre Relay: https://geyser.fund/project/librerelay 

 Ah. So more permissive than Core but not quite pure consensus valid relaying. Thank you.  

 Correct! 

 (n_n)