Yes, the display is square and about 35mm diagonally (although the edges are masked off with a slightly rounded edge). I don't see the link you put to waveshare's module but it's a pretty standard 240x240 colour LCD screen that you'll see in a bunch of places.
In terms of apps - it's a lot. Just checked and the average size of an app in the app loader is 2kB (although I'd expect that to grow!) - however there's 4MB of flash memory so you could theoretically install over 1000.
some pics of the expected hardware attached. Outer dimensions of 240x240 pixel display is 26.3x29.3 mm with active are of about 24.0x24.0 mm. Placement relative to round view port is therefore 1.5mm off center and most top left and top right corner areas - about 14x14 pixels are 'diagonally' covered (that's why the display of latitude - of original software - is inset from the right border.)
Display is considered a 1.3" display - diagonal (EDITED from: 1" or 0.95" | 0.96" display - sides).
NB: All measurements not from datasheet but calipered / derived from actual components and pictures there of.
Regarding number of apps: no experience yet.
Display is considered a 1" or 0.95" | 0.96" display
I think it's bigger than that. Usually displays are measured diagonally.
If you look at https://www.waveshare.com/1.3inch-lcd-module.htm it mentions 23.4×23.4 display size but 1.3 inches.
@Gordon and @allObjects Thank you for the replies and the photos with the watch dismantled. I now have an idea of how big the watch and display is in real-life.
Can i replace the display with a circular one?
Maybe this -> https://m.aliexpress.com/item/32920192414.html?spm=a2g0n.seo-amp-detail.productBottomBar.viewDetails
Will it create any resolution issues with apps?
Well, it's the same display resolution and driver - however Bangle.js uses an 8 bit parallel interface, and that display is serial.
You may be lucky and find that all the pins on the connector are similar enough that everything will work with some modifications to the Espruino firmware, but honestly I think it's very unlikely.
And it definitely won't 'plug and play' :(
I just watched the nodeconf and have gone through the kickstarter page, I am a fan and can't wait to get my hands on it!
The instant question I have is that the display is not the entire screen but a square display [Similar to that of Waveshare's module].
Is the dimension of the actual display unit around 35.8mm? Also, how many light-weight apps could a user install ?