This diff adds a new metadata entry type that provides a catch-all for users who want to display more interesting stuff in the log view. It was suggested in https://github.com/dagster-io/dagster/issues/3416 and seemed like it'd be useful, but I wouldn't object if we want to postpone this in favor of more codified graphing support later.
By default, HTML you provide is shown as [Show HTML] and the modal displays the content within a sandboxed iframe. If you pass inline=True, we trust you know what you're doing and allow the HTML to appear directly within the metadata entries table in the logs. This allows you to do cool stuff, but largely requires that your HTML snippet have a fully specified or immediately calculatable size and is fairly small. The screenshots below show it being used to embed an SVG with a bar chart, and a small image.