Ability to toggle visibility of subscription list from anywhere

It would be useful if the subscription list's visibility could be toggled from any page, such as a show/hide subs icon in the header.

In its current layout there doesn't appear to be a dedicated button to access the subscription list, which means the user has to click the back button anywhere from once to a few times depending on the context to switch to a different sub.

For my device the regular view mode is a suitable width for reading:

On the Tablet Mode view I get the bonus of a visible subs list but at the expense of the list taking up space:

Being able to toggle the subs list into view when needed, and hide while not being used, would be a handy addition for both modes.

Start by locating the subscription-list UI, the regular and tablet-mode layouts, and the header or navigation entry points. Trace how the current back-button navigation changes subscriptions, then determine how visibility state should be shared across pages. Done means the list can be shown and hidden from any page without forcing tablet mode, while preserving the existing reading layout.