Index: build/jenkins/pipelines/docker-differential.Jenkinsfile
===================================================================
--- build/jenkins/pipelines/docker-differential.Jenkinsfile
+++ build/jenkins/pipelines/docker-differential.Jenkinsfile
@@ -1,4 +1,4 @@
-/* Copyright (C) 2022 Wildfire Games.
+/* Copyright (C) 2024 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -173,8 +173,8 @@
 		}
 		stage("Data checks") {
 			steps {
-				warnError('CheckRefs.pl script failed!') {
-					sh "cd source/tools/entity/ && python3 checkrefs.py -tax 2> data-errors.txt"
+				warnError('CheckRefs.py script failed!') {
+					sh "cd source/tools/entity/ && python3 checkrefs.py -actx 2> data-errors.txt"
 				}
 			}
 		}
Index: source/tools/entity/checkrefs.py
===================================================================
--- source/tools/entity/checkrefs.py
+++ source/tools/entity/checkrefs.py
@@ -11,6 +11,12 @@
 from scriptlib import SimulTemplateEntity, find_files
 from logging import WARNING, getLogger, StreamHandler, INFO, Formatter, Filter
 
+# The maximum number of players in a 0ad match. This is also the minimum
+# number of AINames necessary in a civ to avoid duplication of names in a
+# match. Note: ensure that this matches the value of MAX_NUM_PLAYERS in
+# source/tools/atlas/AtlasUI/ScenarioEditor/Sections/Player/Player.cpp.
+MAX_NUM_PLAYERS = 8
+
 class SingleLevelFilter(Filter):
     def __init__(self, passlevel, reject):
         self.passlevel = passlevel
@@ -63,6 +69,9 @@
                         " Implies --check-map-xml. Currently yields a lot of false positives.")
         ap.add_argument('-x', '--check-map-xml', action='store_true',
                         help="check maps for missing actor and templates.")
+        ap.add_argument('-c', '--check-civ-data', action='store_true',
+                        help="check civilization json data files for sufficient AINames and other"
+                        " minimum requirements.")
         ap.add_argument('-a', '--validate-actors', action='store_true',
                         help="run the validator.py script to check if the actors files have extra or missing textures."
                         " This currently only works for the public mod.")
@@ -97,6 +106,8 @@
         self.add_auras()
         self.add_tips()
         self.check_deps()
+        if args.check_civ_data:
+            self.check_civ_data()
         if args.check_unused:
             self.check_unused()
         if args.validate_templates:
@@ -197,25 +208,39 @@
                     terrain_name = f.read(length).decode('ascii')  # suppose ascii encoding
                     self.deps.append((str(fp), terrains.get(terrain_name, f'art/terrains/(unknown)/{terrain_name}')))
 
-    def get_existing_civ_codes(self):
-        existing_civs = set()
+    def get_civ_data_from_tag(self, tag):
+        civ_data = []
         for (_, ffp) in sorted(self.find_files('simulation/data/civs', 'json')):
             with open(ffp, encoding='utf-8') as f:
                 civ = load(f)
-                code = civ.get('Code', None)
-                if code is not None:
-                    existing_civs.add(code)
-
-        return existing_civs
+                civ_code = civ.get('Code', None)
+                if civ_code is not None:
+                    result = civ.get(tag, None)
+                    if result is not None:
+                        civ_data.append((civ_code, result))
+
+        return civ_data
+
+    def get_civ_codes_as_set(self):
+        civ_data = self.get_civ_data_from_tag('Code')
+        civ_codes = set()
+        for civ_data in civ_data:
+            civ_codes.add(civ_data[0])
+
+        return civ_codes
+
+    def get_civ_codes_and_ainames(self):
+        civ_codes_and_ainames = self.get_civ_data_from_tag('AINames')
+        return civ_codes_and_ainames
 
     def get_custom_phase_techs(self):
-        existing_civs = self.get_existing_civ_codes()
+        civ_codes = self.get_civ_codes_as_set()
         custom_phase_techs = []
         for (fp, _)  in self.find_files("simulation/data/technologies", 'json'):
             path_str = str(fp)
             if "phase" in path_str:
                 # Get the last part of the phase tech name.
-                if basename(path_str).split("_")[-1].split(".")[0] in existing_civs:
+                if basename(path_str).split("_")[-1].split(".")[0] in civ_codes:
                     custom_phase_techs.append(str(fp.relative_to("simulation/data/technologies")).replace(sep, '/'))
 
         return custom_phase_techs
@@ -680,6 +705,21 @@
                 continue
             self.logger.warning(f"Unused file '{str(self.vfs_to_relative_to_mods(f))}'")
 
+    def check_civ_count(self):
+        civ_codes = self.get_civ_codes_as_set()
+        if len(civ_codes) == 0:
+            self.logger.warning(f"No valid civilizations defined in simulation/data/civs")
+
+    def check_civ_ainame_counts(self):
+        civ_codes_and_ainames = self.get_civ_codes_and_ainames()
+        for civ_code_and_ainames in civ_codes_and_ainames:
+            if len(civ_code_and_ainames[1]) < MAX_NUM_PLAYERS:
+                self.logger.warning(f"civ '{str(civ_code_and_ainames[0])}' has less than the minimum 8 AINames. Add more AINames in order to prevent duplication of AI-controlled player names in a match.")
+
+    def check_civ_data(self):
+        self.check_civ_count()
+        self.check_civ_ainame_counts()
+
 
 if __name__ == '__main__':
     check_ref = CheckRefs()