What does the number three in the box in the upper left of the image mean?

[thusband]

I've looked in help but don't see it.

Here's a screenshot with the file selected and the cursor pointed to it.

Thanks

[Mario]

Stack Counter. You are working with stacks.
See Creating a Stack

[thusband]

Are stacks created with versions? All the images with stacks are versioned. I don't believe I created them on purpose (I have several). I certainly could have in error though.

I can't seem to delete them or view them in Panels/stacks. They all have the stack counter but no stack indicator.

Thanks.

[Mario]

Masters and Versions automatically build a stack.

See Version Stacks

[thusband]

That explains that. Many thanks.

[Mario]

Tip: Left-click the Stack Counter to open the context menu.