Having a chat and learned that art students often learn about a particular painting by copying it. The act of trying to recreate makes you focus on the details you wouldn’t do otherwise. Got me thinking that something similar could be useful in code. Trying to recreate a well-known program, to really understand how a technique works.
When you get notified that the file has changed on disk, and is different from your current buffer:

file has changed since visited or saved.Β  Save anyway?

Then

M-x diff-buffer-with-file

is very useful for seeing what has actually changed.

I tend to get this when I’ve changed something org-related via orgzly on my mobile while I was also changing something on my laptop.

Population of Newcastle is around 300,000. For a point of reference, the population of Manchester is around 500,000.

Although I’m never really sure what the difference is between city, urban and metro populations.