How to get/set description of constant-combinator or decider-combinator?

ghost_unit_number
I create entity, click on it, it prints `entity` `499`.
I deconstruct entity, press Ctrl+Z, click on ghost, and it prints `ghost` `nil`.

local function create_gui(player, entity)
game.print("entity")
game.print(entity.unit_number)
end
local function create_ghost_gui(player ...

Where should I store data between deconstruction and cancelling deconstruction (Ctrl+Z) and
How should I set ghost_entity.tags? (On which event? and How to understand which real former entity corresponds to the restored ghost? (real former entity and restored ghost have different `unit_number`s))

Can I store data associated with real entity somewhere in entity object? Is there canonical place for such purposes?

Or I should save it in `storage.some_data[entity.unit_number]` and write boilerplate code for transferring it between `storage` and `ghost_entity.tags` for numerous events?

Documantation says:
Note that the API returns tags as a simple table, meaning any modifications to it will not propagate back to the game. Thus, to modify a set of tags, the whole table needs to be written back to the respective property.

I try:

script.on_event(defines.events.on_built_entity ...

Also useful option would be to control enabling "trash unrequested" mode in blue chest by some signal letter (like controlling inserter capacity in inserters)

steps to reproduce:
1) build or destroy some object A (lamp for example)
2) change settings of some another object B (for example set filters in some inserter)
3) press Ctrl+Z

expected behavior:
settings of object B will be the same as it was before
OR settings of object B will be the same as it ...

Please, add capability to add description for lamp like for Display panel or for any other combinators

I would also like to suggest make an option in blue chests (and other storages with requests) to "read the contents, including the contents of robots involved by this chest."
How robots work: Upon receiving a request, the robot reserves the requested items = subtracts robot's capacity from the total ...

I can inserter simultaneously connect to two cirquits: by one set filters and by another read hand contents.
But for requester chest I can only choose between set requests and read contents.
Feature request: make independent capabilities of set requests and read contents for requester chest.