User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36

Steps to reproduce:

BETA 114.0b5. Started TB and new mail came in.

I think this is my browser user agent, not sure!
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/113.0.0.0 Safari/537.36

Actual results:

There is often no bubble showing new email count for each account when the view of my 12 email accounts is 'collapsed.'
Also, when hovering over a folder, it no longer opens to show sub-folders. I have to click on the '>.'

Expected results:

Stated above.

I'm not sure what bubble you're referring to?

Sub-folders never expanded unless you click the twisty.

1-next to the unexpanded e-mail account name/address in the left column, the number of unread e-mails showed as a white number on a blue circle background.
2-the old version would expand a folder by hovering on it for several seconds. Now it does not.

For #1, such an indicator shows for me. (Try Help | Troubleshoot mode)
For the hovering, I think you're mistaken. If you had something like that, maybe that functionality was provided by an add-on.

The hovering 'bug' is not a bug, but my mistake. When dragging an e-mail to a collapsed folder, the folder will open to show subfolders and that works as it did before.

Additional clarification: When I open a collapsed e-mail account, the total of unread new e-mails is shown in a 'bubble' next to the various e-mail folders and when collapsed the bubble is present next to the e-mail account name where it was not shown before expanding the e-mail accoutn.

The area above an open e-mail message does not appear for quite a few seconds (sometimes 30) when displaying. This is the area that has the Reply, Forward, Archive, Junk, Delete, More... It will suddenly pop in after a while.

Are you still seeing this in 115.0b5?

Yes. I downloaded the update to 115.0b5 today and still the same result. It is easy to duplicate as fowwlos:
-Collapse all accounts to a single line EACH in the lefthand pane.
-Send some email to one of the accounts and wait a minute or two to make sure it has had time to be delivered.
---N.B. The account should be shown in blue bold, but some of mine do and others don't (AOL account specifically do not).
-Click the '>' next to the account.
-Once it is expanded, there should be a 'bubble' next to the inbox showing the number of unread emails.
-If I collapse the account by clicking the down arrow next to the account name, a bubble now appears next to the account name showing the number of unread emails.

I find this useful as I have a dozen accounts and can easily find the ones with new email without opening (expanding) the account.