mod in use analysis.

This has been asked by a few people to add to SEToolbox, something to analysis how many of the mods are in use.

One variation was.

Enhance the toolbox by reporting what mods are needed when exporting a ship/station

A second variation is.

I'd like a way to generate a list of mods with placed blocks within a savegame. The purpose being to identify those mods I can remove without consequence to improve load times when loading anothers worlds/scenarios.

I haven't wanted to add to SEToolbox, because it currently doesn't operate with a 'the mod must exist' requirement.
And if hasn't been downloaded, it cannot check because accessing the SteamAPI to download undownloaded mods is getting messy,

But I just found this in the API, which may be all that is required to check mods.
MyDefinitionBase has the public MyModContext Context field.

Start by reviewing the SEToolbox export and savegame-analysis entry points described in the issue, then inspect MyDefinitionBase.Context and MyModContext. Define how placed blocks and exported ships or stations should produce a mod list, including cases where a mod is not downloaded. Done means the requested mod-use report is specified and works without requiring every mod to exist locally.