So there are several ideas posted similar to this one such as notes on mind maps, and automating the use of metadata, but the way I read them they are fairly rich features toward a specific use case. They take the idea of metadata within a board much further than I’m thinking.
Metadata on shapes and lines is something I can see being used in many cases from sprint planning and business process design, to engineering/architectural design. Essentially a key/value store for shape metadata.
Idea: Allow us to create custom fields of metadata on board objects such as shapes and lines, building upon the shape Info feature that already uses metadata to track the creation and mofication info.

An example would be when I draw floor plans, I would use the metadata to record (a) information like the ceiling height (stud) or elevation of a feature on a wall that Miro can’t depict visually as its predominantly 2D orientated and (b) to tag the shape/line with information like the material class and type e.g. Timber H1.2.
Of course once the meta data is in there people are naturally going to want to get it out again, this would be a natural fit to the existing CSV board export feature in Miro.
The other likely next step people would want is a field manager to control what metadata fields exist on the board objects. Personally I would leave this to stand on its own two feet as a separate idea/feature. For example auto-complete when adding a field name to a shape, using existing field names on other objects, could be a solution instead of a management UI like what we use today to manage layers.

