Remove Internet Explorer leftovers

scss/forms/_form-control.scss

@@ -22,12 +22,6 @@
   @include box-shadow($input-box-shadow);
   @include transition($input-transition);
 
-  // Unstyle the caret on `<select>`s in IE10+.
-  &::-ms-expand {
-    background-color: transparent;
-    border: 0;
-  }
-
   // Customize the `:focus` state to imitate native WebKit styles.
   &:focus {
     color: $input-focus-color;

scss/forms/_form-file.scss

@@ -11,13 +11,6 @@
   margin: 0;
   opacity: 0;
 
-  // Separate rules for :focus and :focus-within as IE doesn't support the latter, and
-  // thus ignores the entire ruleset. See https://github.com/twbs/bootstrap/pull/29036.
-  &:focus ~ .form-file-label {
-    border-color: $form-file-focus-border-color;
-    box-shadow: $form-file-focus-box-shadow;
-  }
-
   &:focus-within ~ .form-file-label {
     border-color: $form-file-focus-border-color;
     box-shadow: $form-file-focus-box-shadow;

scss/forms/_form-select.scss

@@ -57,11 +57,6 @@
     border-color: $form-select-disabled-border-color;
   }
 
-  // Hides the default caret in IE11
-  &::-ms-expand {
-    display: none;
-  }
-
   // Remove outline from select box in FF
   &:-moz-focusring {
     color: transparent;