In relation to my Endless Moons mod, I have a module that lets you reduce moon anomalies. It only works for moon exploration because the module reduction value is 0.1 and moon exploration is a 1 turn cost. So it will complete the moon reduction but other anomalies would take 1000s of turns. (This is mostly used by players to hunt for Endless Temples ouside of their territory.)

This is admittadly a bit of a kludge, but it worked before Umbral Choir.

Now, however, the fleet button is greyed out if a player doesn't also have an anomally reduction technology. This is despite having a modded Entity Action concerning anomally reductions, to count my modded tech as a valid prequisite.

During troubleshooting, I temporarily removed both the check for NetAnomalyReductionProduction and for the reduction techs, yet the fleet button is still complaining about needing an anomaly reduction tech, despite those requirements removed.

This makes me think that this check is now hard-coded, or there's another check somewhere else.

Any ideas?

The other thing that has occoured to me, is that perhaps the modded file isn't getting loaded correctly - and this would explain why disabling prerequisites had no effect.

Here's the method I'm using (copied straight out of DataTypes.txt):

            <DatabasePlugin DataType="EntityActionDefinition, Assembly-CSharp" >
                <ExtraTypes>
                     <ExtraType DataType="InitiateEmpireActionFleetActionDefinition, Assembly-CSharp" />
                </ExtraTypes>
                <FilePath>Simulation/EM_EntityActions.xml</FilePath>
            </DatabasePlugin>

Well, I still don't know what's causing the problem, but I found a work-around by hijacking the default Moon Exploration tech.