CVS was notorious for doing "text/binary" conversions (CR/LF line endings to CR and vice versa), sometimes inappropriately. More than once, it resulted in files where every other line was empty. I can very well see this happening several times, resulting in exponential growth of whitespaces.
Assuming a key repeat rate of 15Hz (a number I admittedly just pulled out of thin air), they would have had to lean on the Tab key for almost exactly 1 week.
The guy ate, slept, possibly got married while his finger was still accidentally holding down that key.
CVS was notorious for doing "text/binary" conversions (CR/LF line endings to CR and vice versa), sometimes inappropriately. More than once, it resulted in files where every other line was empty. I can very well see this happening several times, resulting in exponential growth of whitespaces.