You can use the
debugsnippet to debug snippet filters. Snippet debugging works by logging messages to the browser's console about the snippet and its current status.
Consider the following example:
example.com#$#debug; log Hello
In this filter, the
debugsnippet after the domain sets a debugging flag that remains true until the end of the snippets chain. Because you can chain multiple snippets into a single filter,
debugaffects all snippets in the filter.