LibreOffice has already the ability to use links to slides in other presentations. But there is no tool to manage such links, for example to remove linking from an individual slide or to change the link reference for the case the linked presentation has changed name or place.

The part in Edit > Links, which can be uses for linked objects, is not available for linked slides.

I think the next step could be to get a proposal, how such tool could look like.

*** Bug 138730 has been marked as a duplicate of this bug. ***

Heiko will soon comment here following the discussion in the design meeting, but there are three potential issues here:

1. Should there, or should there not, be a Master Presentation like in Writer - that's the title of this bug.
2. Does Impress offer appropriate UI for managing inserted linked slides (which are one way to achieve something similar to a Master Document, but not quite that)
3. Should there, instead of a Master Presentation, be some facility for managing a (sequential) collection of presentations, not linked slides - which seems to be the use case OP is bringing up with their post on ask.libreoffice.org

I believe it's best to separate all of these into their own bugs, since one can have any combination of positions about each of these three IMHO.

Created attachment 195830 [details]
Mockup

We discussed the topic in the design meeting.

The use case is to manage a series of presentation. Unlike master document in Writer the goal is not to combine/export the set but 
a) define a sequence of existing presentations (clear, edit, add)
b) store the sequence (load, save)
c) open a presentation (open)
d) remember the last position (slide number of total number, last open date/time, reset the timings)

The attached mockup shows the basic idea. Slide numbers and date update and become stored automatically. Save As would store the set under a new name with clear timings. I suggest to keep the feature as simple as possible and to not show some indicator for modifications, for example. If the presenter jumps back to a previous slide the number adjusts accordingly. For example going back to slide #5 from lesson 3 results in 3/28 on this line. But if necessary I can imagine another command in the hamburger menu "Mark as finished".

This tool might be realized per extension, could be a GSoC project, and may also be a standalone tool.

The proposal looks nice.
I would miss a "replace presentation".

Imagine you use one sub-presentation in several master.
After upgrading it by "edit presentation" in one master, 
you would like to change in the other ones.

(In reply to Vincent Boudry from comment #5)
> After upgrading it by "edit presentation" in one master, 
> you would like to change in the other ones.

I would expect that modifications are loaded everywhere. I don't see a manager as some kind of cache or storage, it just handles links.

(In reply to Heiko Tietze from comment #4)
> Created attachment 195830 [details]
> Mockup
> ..
Nice :)

> c) open a presentation (open)
> d) remember the last position (slide number of total number, last open
> date/time, reset the timings)
> 
> The attached mockup shows the basic idea. Slide numbers and date update and
> become stored automatically.
Is the idea, or may I suggest, that when opening a presentation to be added to the list, one can use the Slide Sorter to select slides, which selection is then used for the column with slide numbers?
(One could even use a single presentation as source multiple times, for different places in the final 'show'.)

(In reply to Cor Nouws from comment #7)
> Is the idea, or may I suggest, that when opening a presentation to be added
> to the list, one can use the Slide Sorter to select slides...
That goes way beyond my idea. The envisioned manager wouldn't integrate with Impress and could actually be implemented as extension or run as standalone tool.