Erik Dahlström

Related to #89, #399

Support for compression was added in [3D Tiles Archive Format 1.1.pdf](https://github.com/CesiumGS/3d-tiles/files/6115704/3D.Tiles.Archive.Format.1.1.pdf).

The restrictions for being entirely self-contained were lifted in [3D Tiles Archive Format 1.3.pdf](https://github.com/CesiumGS/3d-tiles/files/7442078/3D.Tiles.Archive.Format.1.3.pdf).

The specification (and copies of the older drafts) have been moved to new repo https://github.com/erikdahlstrom/3tz-specification.

This also affects the external 3DTILES_metadata schemas (https://github.com/CesiumGS/3d-tiles/tree/main/extensions/3DTILES_metadata#schema), which are JSON. Ideally they should also have their own mime type (and possibly file extension).

Another idea: add a property that let's one define one or more custom variables for use with the template URI syntax. The variable values could be defined e.g as tile...

I'd recommend that you don't put that <source> element directly into the svg output. I think wrapping it in a <desc> or <metadata> would be better (see https://svgwg.org/svg2-draft/struct.html#UnknownElement for why).

@aaronfranke I'm leaving this for @bjornblissing to answer, as I'm no longer with Maxar.

I'm going to refer to @bjornblissing for this, as I'm no longer with Maxar. From memory, we shipped some content using this extension, so this is documenting that snapshot. However,...