From the docket (https://webapps.sftc.org/ci/CaseInfo.dll?CaseNum=CGC24612746, if links work correctly), it seems that this is Musk dismissing the case without prejudice (i.e., he can litigate the claims again if he wants) on the eve of a hearing asking the case to be dismissed with prejudice (i.e., precluding him from litigating the claims again).
Which makes me think this is a "you can't fire me because I quit" kind of action.
Which makes me think this is a "you can't fire me because I quit" kind of action.