The title literally says "Over the past 21 months I've written a code editor from the ground up". The linked blog post is titled "How to Write a Code Editor from Scratch in 4 Months".
I don't know what you would consider "from the ground up" or "from scratch", but in my view that means no external libraries, if something isn't in the standard library I code it myself. That means that someone only needs a compiler and the standard library to build the application, rather than having to either use a dependency manager or (worse) track down and build the dependencies themselves.
The title literally says "Over the past 21 months I've written a code editor from the ground up". The linked blog post is titled "How to Write a Code Editor from Scratch in 4 Months".
I don't know what you would consider "from the ground up" or "from scratch", but in my view that means no external libraries, if something isn't in the standard library I code it myself. That means that someone only needs a compiler and the standard library to build the application, rather than having to either use a dependency manager or (worse) track down and build the dependencies themselves.