What is the regex for these complex metadata which contain elements, ids, XML and base64?

Hi,

I would like to search elements to remove Gravit metadata and its base64 (<![CDATA[...==]]>) to optimise the SVG files. Here are:

<gravitDesigner:gravitElementRef xmlns:gravitDesigner="http://ns.gravit.io/" xlink:href="#...."/>

<gravitDesigner:gravitGraphicSource xmlns:gravitDesigner="http://ns.gravit.io/" id="..." version="1">
  <![CDATA[...==]]>
</gravitDesigner:gravitGraphicSource>