At the moment they are div which is not the best for accessibility.
I'm used to navigate with my keyboard and this is not possible on storybook.
I can make PR only if you show me where the code of that left navigation bar is (can't find it in the code)

Most of the UI code is available here:
https://github.com/kadirahq/storybook-ui
The storybook list component is in this directory. I think the file you're looking for is this
edit: add link to file
Usually, we should prefer <ul> or <ol> to display a list too
PR time guys !
PR done ! Could you @mnmtanish please review it ?
@jmfrancois with pleasure :)
Most helpful comment
Usually, we should prefer
<ul>or<ol>to display a list too