diff --git a/Include/modsupport.h b/Include/modsupport.h
index 833e33d..39be128 100644
--- a/Include/modsupport.h
+++ b/Include/modsupport.h
@@ -176,7 +176,7 @@
 #endif /* New in 3.5 */
 
 #ifndef Py_LIMITED_API
-PyAPI_DATA(char *) _Py_PackageContext;
+PyAPI_DATA(const char *) _Py_PackageContext;
 #endif
 
 #ifdef __cplusplus
diff --git a/Misc/NEWS b/Misc/NEWS
index b9448dd..5bf35ef 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -416,6 +416,9 @@
 C API
 -----
 
+- Issue #28748: Private variable _Py_PackageContext is now of type "const char *"
+  rather of "char *".
+
 - Issue #19569: Compiler warnings are now emitted if use most of deprecated
   functions.
 
diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
index 701bcb1..350f3bf 100644
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -188,7 +188,7 @@
        (if the name actually matches).
     */
     if (_Py_PackageContext != NULL) {
-        char *p = strrchr(_Py_PackageContext, '.');
+        const char *p = strrchr(_Py_PackageContext, '.');
         if (p != NULL && strcmp(module->m_name, p+1) == 0) {
             name = _Py_PackageContext;
             _Py_PackageContext = NULL;
diff --git a/Python/importdl.c b/Python/importdl.c
index f56fa94..d8656b9 100644
--- a/Python/importdl.c
+++ b/Python/importdl.c
@@ -94,7 +94,7 @@
 #endif
     PyObject *name_unicode = NULL, *name = NULL, *path = NULL, *m = NULL;
     const char *name_buf, *hook_prefix;
-    char *oldcontext;
+    const char *oldcontext;
     dl_funcptr exportfunc;
     PyModuleDef *def;
     PyObject *(*p0)(void);
diff --git a/Python/modsupport.c b/Python/modsupport.c
index 35b529b..06bdcab 100644
--- a/Python/modsupport.c
+++ b/Python/modsupport.c
@@ -9,7 +9,7 @@
 static PyObject *va_build_value(const char *, va_list, int);
 
 /* Package context -- the full module name for package imports */
-char *_Py_PackageContext = NULL;
+const char *_Py_PackageContext = NULL;
 
 /* Helper for mkvalue() to scan the length of a format */