A lot of development time is wasted searching through solution explorer because it shows files based on how they are stored on the file system rather than how they are likely to be used by the programmer. Often times files that typically modified together are not close to each other on the file system and may not be easy to find without a detailed knowledge of the architecture of the code.
Solution explorer is basically like a database for files that has a fixed structure where a file can only appear in a single place. To improve this we create an "index" for a file based on the git history. Files that are typically modified along with a given file will now appear directly nested underneath it as links. This way it is faster to find the files that you are likely to actually use.