LIMWA is based on Data provided by the InSight lander. An empty site indicates that a huge part of data is missing (as currently because the InSight lander has done some weird maneuvering). The site will reappear again if enough data was provided in the last few days.
LIMWA is an Open Source project. If you have any suggestions or want to improve the app, just contact me, open an issue or make a pull request yourself.