## Motivation / Problem

<!--

Describe here shortly

* For bug fixes:

    * What problem does this solve?

    * If there is already an issue, link the issue, otherwise describe the problem here.

* For features or gameplay changes:

    * What was the motivation to develop this feature?

    * Does this address any problem with the gameplay or interface?

    * Which group of players do you think would enjoy this feature?

-->

## Description

<!--

Describe here shortly

* For bug fixes:

    * How is the problem solved?

* For features or gameplay changes:

    * What does this feature do?

    * How does it improve/solve the situation described under 'motivation'.

-->

## Limitations

<!--

Describe here

* Is the problem solved in all scenarios?

* Is this feature complete? Are there things that could be added in the future?

* Are there things that are intentionally left out?

* Do you know of a bug or corner case that does not work?

-->

## Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

* The bug fix is important enough to be backported? (label: 'backport requested')

* This PR affects the save game format? (label 'savegame upgrade')

* This PR affects the GS/AI API? (label 'needs review: Script API')

    * ai_changelog.hpp, gs_changelog.hpp need updating.

    * The compatibility wrappers (compat_*.nut) need updating.

* This PR affects the NewGRF API? (label 'needs review: NewGRF')

    * [PR must be added to API tracker](https://wiki.openttd.org/en/Development/NewGRF/Specification%20Status)