ok so it will get more convenient to open tracks when the full game is released. got it!

You can open and immediately play any map using the command line parameters of ManiaPlanet:
ManiaPlanet.exe /useexedir /singleinst /file=My.Map.Gbx

If you are familiar with *.reg files, you can register a "Open with ManiaPlanet" command in the context menu of Gbx files:
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Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\TrackMania.gbx\Shell\ManiaPlanet]
@="Open with ManiaPlanet"

[HKEY_CLASSES_ROOT\TrackMania.gbx\Shell\ManiaPlanet\Command]
@="\"C:\\\Program Files\\\ManiaPlanet\\\ManiaPlanet.exe\" /useexedir /singleinst /file=\"%1\""
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You have to customize the file path to your location of ManiaPlanet.exe!!

Undo this extension before installing the full game:
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Windows Registry Editor Version 5.00

[-HKEY_CLASSES_ROOT\TrackMania.gbx\Shell\ManiaPlanet]
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