Why? - Because Google refuses to put the iconsets into separate repositories.
Using npm or bower installation will not install the html previews.
npm install md-icons-svg-sprites-24px
bower install md-icons-svg-sprites-24px
Material Design icons are the official icon set from Google that are designed under the material design guidelines. To find all the sets please visit the official github repo.
These icons are courtesy the folks at Google provided under the Creative Common Attribution 4.0 International License (CC-BY 4.0). Feel free to fork this repo for your own use. Please get in touch with me if you are interested in maintaining or contributing repos under the material-design-icon organization at github.