Ingame readme viewer

[planetmaker]

As of r23178 OpenTTD offers to show the readme.txt file, if such file is bundled within the same tar file as the NewGRF itself. Such readme file can optionally be added to the bundle uploaded to bananas, so that it is easy to distribute it along with the NewGRFs.

And NewGRF authors: off to the keyboard and write or improve the readme.txt to accompany the next version of your newgrfs Simply upload a zip file which bundles the grf and readme.txt when updating an existing or uploading a new NewGRF and you're safe when using BaNaNaS.

This is a double posting. Please discuss this feature over there