Some of your website visitors may have browser extensions installed that inject 3rd party code into your website. This content is sometimes detected by Localize alongside your real website content and placed into Phrases page.
To prevent Localize from detecting 3rd party content from browser extensions, wrap your website content in an element with an ID of localizejs. For example:
<!-- Your website content here -->
Then set the initialization option translateBody to false.
This instructs Localize to only detect content within the wrapper element, <div id="localizejs">. Since 3rd party content from browser extensions is typically injected outside of this wrapper element, it will not be detected by Localize.