debug/css/screen.css

Using height with border can sometimes make elements larger than you expect.
4
border: 1px solid #ccc;

dist/leaflet.css

The property -ms-user-select is compatible with -webkit-user-select and -moz-user-select and should be included as well.
25
-webkit-user-select: none;
The property -ms-transform-origin is compatible with -webkit-transform-origin and should be included as well.
38
-webkit-transform-origin: 0 0;
Use of !important
50
max-width: none !important;
The property -webkit-box-sizing is compatible with -moz-box-sizing and should be included as well.
62
-moz-box-sizing: border-box;
The property -webkit-user-select is compatible with -moz-user-select and should be included as well.
68
-moz-user-select: none;
Unknown property 'will-change'.
142
will-change: opacity;
Unknown property 'will-change'.
160
will-change: transform;
Element (a.leaflet-active) is overqualified, just use .leaflet-active without element name.
216
.leaflet-container a.leaflet-active {
Using height with border-bottom can sometimes make elements larger than you expect.
240
border-bottom: 1px solid #ccc;
Element (a.leaflet-disabled) is overqualified, just use .leaflet-disabled without element name.
267
.leaflet-bar a.leaflet-disabled {
Using height with padding can sometimes make elements larger than you expect.
442
padding: 1px;
Using height with padding can sometimes make elements larger than you expect.
462
padding: 4px 4px 0 0;

spec/expect.js

Expected '===' and instead saw '=='.
253
'object' == type
Expected '{' and instead saw 'throw'.
813
throw new TypeError();
'rv' used out of scope.
840
return rv;

spec/sinon.js

Expected '{' and instead saw 'return'.
84
if (!func) return "";
Expected '!==' and instead saw '!='.
514
if (typeof method != "function") {

spec/suites/SpecHelper.js

Extending prototype of native object: 'Array'.
2
Array.prototype.map = function (fun) {

src/control/Control.Layers.js

The body of a for in should be wrapped in an if statement to filter unwanted properties from the prototype.
141
for (i in this._layers) {