wpsnoop [clear] shortcode is used by 17 plugins and 2 themess

WordPress Shortcodes are used to create visual effects like [bold] text [/bold]

Shortcodes can also be used to embed Videos, Calendars, Tables, Products, Product Reviews, GitHub badges, source code, almost anything - and therein lies the great benefit of WordPress shortcodes and also the problem of conflicting plugins competing to try to make [clear] a shortcode appear on a page.

This page provides some information on the clear shortcode and a list of plugins and themes that implement it.