Gosh. How come, if you don't mind my asking?

Because of what my company calls a "sabbatical", and other companies who implement similar schemes give names such as "extended service leave". Essentially, it's a contiguous 4-week paid holiday in addition to my normal leave allowance for the year, granted as a reward for four years of service. In this case, it's my second one; I took my first this time four years ago.

Ah, yes, we call them sabbaticals too, but it's not clear to me what happens here after eight years' service; one unsubstantiated rumour says that instead of a second sabbatical, one gets a permanent annual leave increase of 5 days per year.