diff --git a/swh/loader/package/maven/loader.py b/swh/loader/package/maven/loader.py
--- a/swh/loader/package/maven/loader.py
+++ b/swh/loader/package/maven/loader.py
@@ -4,7 +4,6 @@
 # See top-level LICENSE file for more information
 
 from datetime import datetime, timezone
-import hashlib
 import json
 import logging
 from os import path
@@ -29,7 +28,6 @@
 from swh.loader.package.loader import (
     BasePackageInfo,
     PackageLoader,
-    PartialExtID,
     RawExtrinsicMetadataCore,
 )
 from swh.loader.package.utils import EMPTY_AUTHOR, release_name
@@ -46,9 +44,6 @@
 
 logger = logging.getLogger(__name__)
 
-EXTID_TYPE = "maven-jar"
-EXTID_VERSION = 0
-
 
 @attr.s
 class MavenPackageInfo(BasePackageInfo):
@@ -64,21 +59,8 @@
     # default format for maven artifacts
     MANIFEST_FORMAT = string.Template("$gid $aid $version $url $time")
 
-    def extid(self, manifest_format: Optional[string.Template] = None) -> PartialExtID:
-        """Returns a unique intrinsic identifier of this package info
-
-        ``manifest_format`` allows overriding the class' default MANIFEST_FORMAT"""
-        manifest_format = manifest_format or self.MANIFEST_FORMAT
-        manifest = manifest_format.substitute(
-            {
-                "gid": self.gid,
-                "aid": self.aid,
-                "version": self.version,
-                "url": self.url,
-                "time": str(self.time),
-            }
-        )
-        return (EXTID_TYPE, EXTID_VERSION, hashlib.sha256(manifest.encode()).digest())
+    EXTID_TYPE = "maven-jar"
+    EXTID_VERSION = 0
 
     @classmethod
     def from_metadata(cls, a_metadata: Dict[str, Any]) -> "MavenPackageInfo":
@@ -116,10 +98,9 @@
         storage: StorageInterface,
         url: str,
         artifacts: Sequence[Dict[str, Any]],
-        extid_manifest_format: Optional[str] = None,
         max_content_size: Optional[int] = None,
     ):
-        f"""Loader constructor.
+        """Loader constructor.
 
         For now, this is the lister's task output.
         There is one, and only one, artefact (jar or zip) per version, as guaranteed by
@@ -142,10 +123,6 @@
 
                - **version**: artifact's version
 
-            extid_manifest_format: template string used to format a manifest,
-                which is hashed to get the extid of a package.
-                Defaults to {MavenPackageInfo.MANIFEST_FORMAT!r}
-
         """
         super().__init__(storage=storage, url=url, max_content_size=max_content_size)
         self.artifacts = artifacts  # assume order is enforced in the lister
diff --git a/swh/loader/package/maven/tests/test_maven.py b/swh/loader/package/maven/tests/test_maven.py
--- a/swh/loader/package/maven/tests/test_maven.py
+++ b/swh/loader/package/maven/tests/test_maven.py
@@ -6,7 +6,6 @@
 import hashlib
 import json
 from pathlib import Path
-import string
 
 import pytest
 
@@ -541,31 +540,9 @@
 
     p_info = MavenPackageInfo(**metadata)
 
-    expected_manifest = (
-        b"al.aldi sprova4j 0.1.0 "
-        b"https://repo1.maven.org/maven2/al/aldi/sprova4j/0.1.0/sprova4j-0.1.0"
-        b"-sources.jar 1626109619335"
-    )
-    for manifest_format in [
-        string.Template("$aid $gid $version"),
-        string.Template("$gid $aid"),
-        string.Template("$gid $aid $version"),
-    ]:
-        actual_id = p_info.extid(manifest_format=manifest_format)
-        assert actual_id != ("maven-jar", hashlib.sha256(expected_manifest).digest(),)
-
-    for manifest_format, expected_manifest in [
-        (None, "{gid} {aid} {version} {url} {time}".format(**metadata).encode()),
-    ]:
-        actual_id = p_info.extid(manifest_format=manifest_format)
-        assert actual_id == (
-            "maven-jar",
-            0,
-            hashlib.sha256(expected_manifest).digest(),
-        )
-
-    with pytest.raises(KeyError):
-        p_info.extid(manifest_format=string.Template("$a $unknown_key"))
+    expected_manifest = "{gid} {aid} {version} {url} {time}".format(**metadata).encode()
+    actual_id = p_info.extid()
+    assert actual_id == ("maven-jar", 0, hashlib.sha256(expected_manifest).digest(),)
 
 
 def test_jar_snapshot_append(