We would like to express our gratitude to both referees for their review and their positive judgement of the article, and to referee 1 for his suggestions for improvement. We tried to follow the suggestions and hope that the amendments to the manuscript are satisfactory.

1. The relation of the feature of the QCD phase diagram to experimental observables is now added in two addtional paragraphs at the end of section 1.

2. We followed the suggestion to include more theoretical scenarios of high-density matter in section 1 and to move the mentioning of the NJL model to this place (p. 4, left column).

3. We updated the bibliography in several places (flow, fluctuations, strangeness). It must be noted, however, that the literature on this topics is vast, and a complete referencing is outside of the scope of this paper. In the text, we chose the references that substantiate the line of our argument, with focus on the consequences for the experimental strategy. Thus, we tried to accomodate the referee's suggestion by adding some "standard" or overview papers for flow and strangeness at the beginning of the sections. The literature on charm is less extensive, in particular for the lower collision energies of relevance here, and we think our referencing adequate in this section. We have added one recent overview article on this topic.


List of changes:

1. Abstract: the year 2022 for first data taking was changed to 2024 according to the new, conservative timeline of FAIR. The same change was done on p.12 at the beginning of section 5.

2. P. 4, left, 2nd paragraph: The two sentences beginning with „The development of a mixed phase…“ was moced to here from the 3rd paragraph in the right column, following the suggestion of referee 1. A sentence referring to alternative scenarios wass added, also following referee 1.

3. P. 4, right, item list: „Do exotiv phases like quarkyonic matter exist“ was changed to „Do exotic phases exist?“ (suggestion of referee 1)

4. P. 5: at the end of section 1, two paragraphs connecting the features of the phase diagram with observables were added (suggestion of referee 1).

5. P. 6_ Figure 3 was updated (max. rate of STAR, label FTX. One sentence mentioning experimental projects under discussion.

6. P. 9, left, 3rd paragraph: One sentence added at the beginning.


Added references:

13, 14 (scenarios for matter at high densities)
33, 34 (review articles on flow)
45 - 48, 58 (fluctuations)
59 - 61 (strangeness)
68 - 70, 73 - 83 (di-leptons)
89 (charm).