The `j` project was a relic from a time when the file input codecs were separate
packages. They have been folded into one project, obviating the `j` project.
The main README can be found at https://docs.sheetjs.com.
Installation instructions are listed in https://cdn.sheetjs.com. `j` drew
upon the utility functions from `xlsx` so migration should be straightforward.
Report issues to https://git.sheetjs.com/sheetjs/sheetjs/issues.
The source code is available at https://git.sheetjs.com/sheetjs/sheetjs.