There is a general consensus that sidechains and LN/sidechain type protocols are Layer 2 on top of the Bitcoin base layer, layer 1.
Many people, including our dear Jack think that the competition is still open to define THE layer 2.
The reality is that Bitcoin will work best when its blocks are filled with HTLCs and building on top of LN gives you a lot more options, you can anchor in the base layer, as needed, such as Fidelity Bonds, and/or you can anchor in the next layer, and provide spam resistance via the use of LN microtransactions.
The main achievement of Bitcoin is finding a way to both stop spammy transactions and distribute the privilege of publishing blocks as widely as possible. The block reward is just an inducement to compensate for the inevitable volatility in the early stages.
When you build on top of LN, you can create protocols that leverage the economics of bitcoin's perfect monetary policy, that can scale freely without any limit, stopping spammy activity, and anchoring your protocol's hierarchy of "stake" in whatever way suits your use case.
Unlike most Proof of Stake blockchains, where it has been proven that early adopters tend to be immovable from their top positions, the liquidity of LN allows a more fluid consensus based on unforgeable sats.
Bitcoin is the foundations. LN is the walls and supporting structures. Layer 3 is the roof which allows us to control the environment in the space between.
netcat
is not an application? Ortelnet
, both of which sit directly above TCP/IP. Indeed, TCP is on top of IP, in fact, it's an application for reliable message transport. The network itself is an application!