User-Agent:       Mozilla/5.0 (X11; Linux x86_64; rv:120.0) Gecko/20100101 Firefox/120.0
Build Identifier: 

After installing, I noticed a lack of font support for a lot of Indic and south Asian languages.

They are both pretty populous areas so it seems like an oversight to not include their basic fonts in the default installation.

Reproducible: Always

Steps to Reproduce:
1. Open Firefox from Flatpak (as installed by default).
2. Go to https://meta.wikimedia.org/wiki/List_of_Wikipedias
3. Look at the "Other languages" box at the top of the page.
Actual Results:  
I see TOFU for several languages including Kannada.

Expected Results:  
I expected to see all languages in that box be rendered by default.

I did a bit of research, and we are talking about at least these ones, listed in order of native speakers counted in millions (based on quick Wikipedia data):

| Language   |   Native Speakers |    L2 Speakers |
| ---------- | -----------------:| --------------:|
| Telugu     |                83 |             13 |
| Kannada    |                44 |             15 |
| Burmese    |                33 |             10 |
| Khmer      |                17 |              1 |
| Santali    |               7.6 |              - |
| Shan       |               4.7 |              - |
| Tulu       |              1.85 |              - |
| Manipuri   |               1.8 |            1.2 |
| Tibetan    |               1.2 |              - |
| Mon        |               0.9 |              - |
| Pa'O       |              0.86 |              - |
| Dzongkha   |              ~0.2 |           ~0.4 |
| ========== | ================= | ============== |
| Total      |    196.11 million |   40.6 million |

While it would be nice to have all of them, I don't think that should be a priority, but having at least fonts for the top ones seems reasonable.

That would be a very small impact while being very useful to a large number of people.

Fedora for instance, have already done some of this research which we could leverage. Which I found here: https://fedoraproject.org/wiki/Changes/Indic_Noto_fonts

It basically would include including these fonts in the pattern, in both Sans and Sans-Serif versions:
- google-noto-sans-bengali-vf-fonts
- google-noto-sans-devanagari-vf-fonts
- google-noto-sans-gujarati-vf-fonts
- google-noto-sans-kannada-vf-fonts
- google-noto-sans-oriya-vf-fonts
- google-noto-sans-tamil-vf-fonts
- google-noto-sans-telugu-vf-fonts

As an alternative, there is the indic-fonts package which Fedora intended to switch away from, Zypper marks it as being only 6.2 MiB when installed. This does not to my knowledge include fonts for Khmer or Burmese, so that would require some additional research.

Unfortunately I don't know any of these languages so I can not comment on any specifics when it comes to which font should be used for which language.