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 # Solana Program Library
 
-The Solana Program Library (SPL) is a collection of Solana-maintained
-on-chain programs.
+The Solana Program Library (SPL) is a collection of on-chain programs targeting
+the [Sealevel parallel runtime](https://medium.com/solana-labs/sealevel-parallel-processing-thousands-of-smart-contracts-d814b378192).
+These programs are tested against [Solana](https://solana.com)'s implementation
+of Sealevel, solana-runtime, and deployed to its mainnet.  As others implement
+Sealevel, we will graciously accept patches to ensure the programs here are
+portable across all implementations.