Dear Arseny,
To take a look at the contents of the infobase whose .dt backup file you have, you need to purchase at least one 1C:Enterprise platform client license.
Then, in the simplest scenario, you install 1C:Enterprise platform, activate the client license, create an empty infobase in file mode (on the same computer where you installed 1C:Enterprise platform), and then restore the infobase contents from the .dt backup.
Best regards,
Vladimir Gurov