These configs are part of the "adding Logstash to filebeat modules getting started experience" and therefore its very likely the first time a user will see a LS config.

For the best experience we should add a fair few comments to better inform what is going on. The user sees the nested field reference for the first time and there is a try three grok pattern scheme with two mutate renames that w

ActorAdapter will ignore null message with "Adapter function returned null which is not valid as an .."

However, this seems not be documented. For instance, scaladoc/javadoc of pipeToSelf could mention it as well as any other place where adapters are used.

Summa

Some of the icons are not self-explanatory, they need tooltips saying what they do

it's becoming more time-consuming and error-prone to manually re-test all the demos following internal refactorings and API adjustments.

now that the API is fleshed out a bit, it's possible to test a large amount of code (non-granularly) without having to simulate all interactions via Puppeteer or similar.

a lot of code can already be regression-tested by simply running all the demos and val