It's not a matter of another script, Image>Canvas size is in standard Gimp.

In practice I "invented"(*) the technique to help someone on a Forum That Shall Not Be Named. Much faster to explain (and perform) than telling him to download a script, install it and run it. It's matter of "bang for the click". Of course, if you need to to this every day, the script is useful, but people also request scripts because they think there is no other way...

(*) Going back in the thread history, I find that this thread started a long while ago, and this is exactly the same as Jolie's suggestion (first reply to O's question). Great minds,... etc

Back when 2.4 was coming out, I proposed that it should be possible to change the canvas size by zero pixels (just so resizing layers should be accommodated). My suggestion was rather resoundingly rebuffed.

And the very next response was basically "thanks but I'd prefer a script", which is my feeling exactly. This is an operation I do often, sometimes 30-40 times per day when working on GIMP projects.

But hey, for those who like to perform twice the work to get the job done, they probably shouldn't bother with a script.

Another great script! Thanks!