Impress. the style of text box(based on master slide)/Font contains 3 fonts: Western Text Font, Asian Text Font and CTL font.
Figure 1 style of the sample file
Untitled 1.odp (13.2 KB)
In Figure 1, I choose 2 popular Chinese fonts, 宋体 and 华文彩云. Western Text Font=宋体, Asian Text Font=华文彩云 and CTL font=华文彩云
(tested: 宋体 can be replaced to other Chinese fonts)
The appearance is 华文彩云, which is right.
Now, I save it as Powerpoint 2007-365 .pptx and upload it to Microsoft Office Online(MS) to open it.
Figure 2, MS thinks the font is DejaVu Sans
However, the appearance is 宋体. In sample, the textbox just contains Chinese characters so choosing Western Text Font is not proper I guess. Besides, I don’t know where DejaVu Sans comes from.
If I reload the .pptx in LibreOffice(LO) I can see all fonts info lost, it goes back to LO default setting.
In conclusion: when converting to MS the information of Western Text Font of style of master slide of textbox is converted but MS can not recognize it fully right, and LO can not recognize it at all. Asian Text Font is not displayed in MS and LO.
Plus: In MS 2019, the appearance is not the font of Western Text Font, but the font of LO default font.
Plus2: When Writer converts to .docx with the paragraph style setting, nothing wrong happens.
Translation to Chinese:
关于ppt或者演示文稿，，，母版幻灯片的文本框的style/fonts包含3种字体：西文字体、亚洲字体和Complex Text Layout字体。
在图一中，我选择了宋体和华文彩云两种流行的中文字体。 Western Text Font=宋体, Asian Text Font=华文彩云 and CTL font=华文彩云
（经测试：宋体可以替换成其他中文字体，不影响试验）
文字看起来是华文彩云，没错。
现在，我将它另存为 Powerpoint 2007-365 .pptx 并用微软Microsoft Office Online(MS) 打开它。文字看起来竟然是宋体！纯中文出了西方文本字体显示起来还是什么DejaVu Sans！
如果我在LO中重新加载 .pptx，我可以看到所有字体信息都丢失了，它看起来是LO默认设置。
总结：转MS后文本框的母版的Western Text Font信息写入了.pptx但MS不能完全识别，LO完全不能识别。 MS和LO中不显示亚洲文本字体。
补充：在MS 2019中完全不能识别，看起来像LO默认的字体。
Writer转.docx就没事。