Looks like it's been knocking about for a year and although they have not updated their website https://www.grimmstar.com/ the game appears to be still in development.
Seems to be a 6dof combat fighter with some fleet building management features, maybe something similar to Starshatter.
Definitely looks good, I hope this game least gets to a state where they can release it because it would be a shame to see it fail after seeing these trailers.
New dev log for the game along with an announcement for anyone who wants to submit a corporation name for the game, details to follow.
And they have uploaded their video for anyone interested in adding a company to the game.