Compare the storage requirements of this game and its many gigabytes to the essentials of D&D plus campaign-specific information.
Three PDFS (i.e., the PHB, DMG and MM) total less than fifty megabytes in size. A text document with campaign notes probably won't exceed a megabyte or two. Throw in high quality maps and you're still well with one-hundred megabytes all-in-all.
Ultimately, human imagination truly possesses the best data compression
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