Ordinarily it requires an excuse for most voters to vote by absentee ballot. The Texas AG has taken the position that fear of contracting COVID-19 is not a valid excuse to vote absentee.
This court order, which was expected, says that voters may put down the disability category if they fear contracting COVID-19 and wish to vote absentee. The AG has already indicated the state will appeal, so this will go up the chain.
There’s also a separate case in federal court.