diff --git a/src/utils.js b/src/utils.js
index 1a6aaee..2a41082 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -211,6 +211,11 @@ function applyShellStylesheet(stylesheet) {
     logDebug('Shell stylesheet applied.');
 }
 
+/**
+ * Check if the given keyval is forbidden.
+ * @param {number} keyval The keyval number.
+ * @returns {boolean} `true` if the keyval is forbidden.
+ */
 function isKeyvalForbidden(keyval) {
     const forbiddenKeyvals = [
         Gdk.KEY_Home,
@@ -229,6 +234,12 @@ function isKeyvalForbidden(keyval) {
     return forbiddenKeyvals.includes(keyval);
 }
 
+/**
+ * Check if the given key combo is a valid binding
+ * @param {{mask: number, keycode: number, keyval:number}} combo An object
+ * representing the key combo.
+ * @returns {boolean} `true` if the key combo is a valid binding.
+ */
 function isBindingValid({ mask, keycode, keyval }) {
     if ((mask === 0 || mask === Gdk.SHIFT_MASK) && keycode !== 0) {
         if (
@@ -250,6 +261,12 @@ function isBindingValid({ mask, keycode, keyval }) {
     return true;
 }
 
+/**
+ * Check if the given key combo is a valid accelerator.
+ * @param {{mask: number, keyval:number}} combo An object representing the key
+ * combo.
+ * @returns {boolean} `true` if the key combo is a valid accelerator.
+ */
 function isAccelValid({ mask, keyval }) {
     return Gtk.accelerator_valid(keyval, mask) || (keyval === Gdk.KEY_Tab && mask !== 0);
 }