Clarification on custom filters documentation

[james-yin]

In the "Custom Filters" documentation section https://github.com/rangav/thunder-client-support/blob/master/docs/filters.md#custom-filters, the following picture has message as part of
{{message | appendString("Custom")}}

So what is this message? I failed to see any references to it. Please clarify, thanks.

[rangav]

Hi @james-yin

• message is env variable
• You can use filters to modify env variable values