diff --git a/gio/gsubprocesslauncher.c b/gio/gsubprocesslauncher.c
index fbcbf6a45..e32f9bdfc 100644
--- a/gio/gsubprocesslauncher.c
+++ b/gio/gsubprocesslauncher.c
@@ -237,9 +237,8 @@ g_subprocess_launcher_new (GSubprocessFlags flags)
  * As an alternative, you can use g_subprocess_launcher_setenv(),
  * g_subprocess_launcher_unsetenv(), etc.
  *
- * All strings in this array are expected to be in the GLib file name
- * encoding.  On UNIX, this means that they can be arbitrary byte
- * strings.  On Windows, they should be in UTF-8.
+ * On UNIX, all strings in this array can be arbitrary byte strings.
+ * On Windows, they should be in UTF-8.
  *
  * Since: 2.40
  **/
@@ -261,10 +260,9 @@ g_subprocess_launcher_set_environ (GSubprocessLauncher  *self,
  * Sets the environment variable @variable in the environment of
  * processes launched from this launcher.
  *
- * Both the variable's name and value should be in the GLib file name
- * encoding. On UNIX, this means that they can be arbitrary byte
- * strings. On Windows, they should be in UTF-8.
- *
+ * On UNIX, both the variable's name and value can be arbitrary byte
+ * strings, except that the variable's name cannot contain '='.
+ * On Windows, they should be in UTF-8.
  *
  * Since: 2.40
  **/
@@ -285,9 +283,8 @@ g_subprocess_launcher_setenv (GSubprocessLauncher *self,
  * Removes the environment variable @variable from the environment of
  * processes launched from this launcher.
  *
- * The variable name should be in the GLib file name encoding.  On UNIX,
- * this means that they can be arbitrary byte strings.  On Windows, they
- * should be in UTF-8.
+ * On UNIX, the variable's name can be an arbitrary byte string not
+ * containing '='. On Windows, it should be in UTF-8.
  *
  * Since: 2.40
  **/
@@ -306,9 +303,8 @@ g_subprocess_launcher_unsetenv (GSubprocessLauncher *self,
  * Returns the value of the environment variable @variable in the
  * environment of processes launched from this launcher.
  *
- * The returned string is in the GLib file name encoding.  On UNIX, this
- * means that it can be an arbitrary byte string.  On Windows, it will
- * be UTF-8.
+ * On UNIX, the returned string can be an arbitrary byte string.
+ * On Windows, it will be UTF-8.
  *
  * Returns: the value of the environment variable, %NULL if unset
  *
diff --git a/glib/genviron.c b/glib/genviron.c
index 0a83ac941..8c64cdaf8 100644
--- a/glib/genviron.c
+++ b/glib/genviron.c
@@ -70,8 +70,7 @@ g_environ_find (gchar       **envp,
  * @envp: (allow-none) (array zero-terminated=1) (transfer none): an environment
  *     list (eg, as returned from g_get_environ()), or %NULL
  *     for an empty environment list
- * @variable: the environment variable to get, in the GLib file name
- *     encoding
+ * @variable: the environment variable to get
  *
  * Returns the value of the environment variable @variable in the
  * provided list @envp.
@@ -218,14 +217,13 @@ g_environ_unsetenv (gchar       **envp,
 
 /**
  * g_getenv:
- * @variable: the environment variable to get, in the GLib file name
- *     encoding
+ * @variable: the environment variable to get
  *
  * Returns the value of an environment variable.
  *
- * The name and value are in the GLib file name encoding. On UNIX,
- * this means the actual bytes which might or might not be in some
- * consistent character set and encoding. On Windows, it is in UTF-8.
+ * On UNIX, the name and value are byte strings which might or might not
+ * be in some consistent character set and encoding. On Windows, they are
+ * in UTF-8.
  * On Windows, in case the environment variable's value contains
  * references to other environment variables, they are expanded.
  *
@@ -248,10 +246,9 @@ g_getenv (const gchar *variable)
  * @value: the value for to set the variable to.
  * @overwrite: whether to change the variable if it already exists.
  *
- * Sets an environment variable. Both the variable's name and value
- * should be in the GLib file name encoding. On UNIX, this means that
- * they can be arbitrary byte strings. On Windows, they should be in
- * UTF-8.
+ * Sets an environment variable. On UNIX, both the variable's name and
+ * value can be arbitrary byte strings, except that the variable's name
+ * cannot contain '='. On Windows, they should be in UTF-8.
  *
  * Note that on some systems, when variables are overwritten, the memory
  * used for the previous variables and its value isn't reclaimed.