Is there a way to list all of the "variables" available?

Is there a way to list all of the variables available?
Variables may be the wrong word but it should be clarified below.

I am a customer of Zendesk and they use Liquid for some of their formatting.
But, they are not the greatest at keeping up with the documentation of the new variables they have created. They call them placeholders.
https://support.zendesk.com/hc/en-us/articles/203662156-Zendesk-Support-placeholders-reference

Use Case: As a user, I would like the ability to use Liquid to output all of the available variables. In my case something like {{listvariables}} would output the following:
user.organization.name
user.organization.is_shared
user.organization.is_shared_comments
user.organization.details
user.organization.notes
user.organization.tags

ticket.comments
ticket.public_comments
ticket.latest_comment
ticket.latest_public_comment placeholders.
ticket.public_comments
ticket.latest_comment
ticket.latest_public_comment

comment.author.name
comment.created_at
comment.created_at_with_time
comment.is_public
comment.value
comment.value_rich
comment.id
comment.attachments
attachment.filename
attachment.url

The issue names no implementation files, entry points, or tests. Start by reviewing Liquid's variable-resolution behavior and the linked Zendesk placeholder reference, then seek maintainer guidance on scope; completion would require an agreed way to enumerate available variables and corresponding tests or documentation.