Linking something in an editor seems fairly simple but it can be quite a complex problem. This was something I worked on extensively.
For example, there are different types of links: posts, pages, outside the CMS links. These also need to be unlinked easily. Icons also can cause issues with comprehension so looking at each was key.
Icons grew to be incredibly important throughout the editor as the balance was made between too little or too much text.
There were also accessibility and SEO considerations along with the need to have an interface because it’s an open source project – that could be extended.