For a front end web dev that makes sense. If you have been working on e.g. internal tools or some other proprietary stuff for a long time, how are you supposed to prove their existence?
Obviously it doesn't apply to everything. But for something like a public website or mobile app that would be reasonably expected to be easily findable, the fact that it isn't is weird. One project like that makes me wonder what the situation is; several make me suspicious.
For what it's worth, some Googling turned up these links:
