Do I have to link to the glyphicon website?
<p>The <a href="https://getbootstrap.com/docs/3.3/components/#glyphicons" rel="nofollow noreferrer">Bootstrap homepage</a> states : </p>

<blockquote>
  <p>Glyphicons Halflings are normally not available for free, but their creator has made them available for Bootstrap free of cost. As a thank you, we only ask that you include a link back to Glyphicons whenever possible.</p>
</blockquote>

<p>- it asks me to "link back to Glyphicons" - is this legally binding ?</p>

<p>Their license is <a href="https://www.glyphicons.com/license/" rel="nofollow noreferrer">here</a>, and it says explicitly</p>

<blockquote>
  <p>You do not have to indicate the name of the author or giving any
  credits to GLYPHICONS.com, although it is always appreciated.</p>
</blockquote>

<p>It is a suggestion and polite request, not a legal requirement. </p>

internet software licensing open-source-software