Starting with the next revision of Unraid (6.10), all html tags within descriptions / overviews / config elements etc is automatically removed by the OS. This includes any thing that can be construed as a tag (ie: "change this entry with <variable> [variable2] here" - <variable> & [variable2] will be removed from the description).
Since 6.9, the edit docker screens have supported Markdown on the descriptions / overviews. (Currently there are no plans to have the config elements support this - and the application feed will still trigger a very nasty blacklisting if it finds any tagging within config elements) The next revision of CA will also support Markdown within the popup descriptions. See here for a live demo of the version of markdown which is incorporated into the GUI
For the most part this security change will not affect anyone. Some old templates that did include some colors within the descriptions will have the colors removed (Markdown does not support colors).
Because Markdown is human readable, if you do create a template overview using markdown, there will be no issues on a user installing that template on a system <6.9.0