W001 - Herst/bootlint-ng GitHub Wiki
Note: Below is the original page from the Bootlint documentation, some of the info here might not apply to Bootlint-NG!
No <meta charset="..."> tag was found in the <head> of the document. If your HTTP server is setting the correct charset in the Content-Type header of its responses, it's safe to ignore this warning because adding a <meta> charset tag would be unnecessary and redundant. Otherwise, we recommend fixing your server's configuration (if possible) and/or adding a <meta charset="..."> tag to your document's <head>.
A <meta charset="..."> tag specifying a non-UTF8 charset was found in the <head> of the document.
UTF-8 is the primary character encoding on the modern web. It's backward-compatible with ASCII, can accommodate all of Unicode, and every modern software platform and programming language can read and write it. We therefore encourage you to use the UTF-8 encoding for your Bootstrapped HTML.
However, Bootstrap itself doesn't care about what encoding you use, and will work fine if you use other encodings, provided that the browser and the web server both understand the encoding and are both configured correctly.