Added trigger conditional for entering era

core/src/com/unciv/logic/civilization/TechManager.kt

@@ -341,6 +341,11 @@ class TechManager : IsPartOfGameInfoSerialization {
             for (era in erasPassed)
                 for (unique in era.uniqueObjects)
                     UniqueTriggerActivation.triggerCivwideUnique(unique, civInfo)
+
+            val eraNames = erasPassed.map { it.name }.toHashSet()
+            for (unique in civInfo.getTriggeredUniques(UniqueType.TriggerUponEnteringEra))
+                if (unique.conditionals.any {it.type == UniqueType.TriggerUponEnteringEra && it.params[0] in eraNames})
+                    UniqueTriggerActivation.triggerCivwideUnique(unique, civInfo)
         }
 
         for (unique in civInfo.getTriggeredUniques(UniqueType.TriggerUponResearch))

core/src/com/unciv/models/ruleset/unique/UniqueType.kt

@@ -700,10 +700,10 @@ enum class UniqueType(val text: String, vararg targets: UniqueTarget, val flags:
     ///////////////////////////////////////// region TRIGGERS /////////////////////////////////////////
 
     TriggerUponResearch("upon discovering [tech]", UniqueTarget.TriggerCondition),
+    TriggerUponEnteringEra("upon entering the [era]", UniqueTarget.TriggerCondition),
     TriggerUponAdoptingPolicy("upon adopting [policy]", UniqueTarget.TriggerCondition),
     TriggerUponDeclaringWar("upon declaring war", UniqueTarget.TriggerCondition),
     TriggerUponEnteringGoldenAge("upon entering a Golden Age", UniqueTarget.TriggerCondition),
-
     //endregion
 
     ///////////////////////////////////////////// region META /////////////////////////////////////////////

docs/Modders/uniques.md

@@ -1875,6 +1875,11 @@ Simple unique parameters are explained by mouseover. Complex parameters are expl
 
 	Applicable to: TriggerCondition
 
+??? example  "upon entering the [era]"
+	Example: "upon entering the [Ancient era]"
+
+	Applicable to: TriggerCondition
+
 ??? example  "upon adopting [policy]"
 	Example: "upon adopting [Oligarchy]"