1 Answer
From your first link:
Remix is a suite of tools to interact with the Ethereum blockchain in order to debug transactions, stored in this Git repository. A Remix transaction Web debugger is available here, and its source code is part of this repository.
The Remix IDE is an IDE for Solidity dApp developers, powered by Remix. The Remix IDE repository is available here, and an online version is available at https://remix.ethereum.org.
