Created attachment 1193167 [details] fedora-25-20160822-khmer-displays-as-replacement-characters.png Fedora-Workstation-netinst-x86_64-25-20160822.n.0.iso See screenshot.
$ fc-list :lang=km family file | grep -v mfabian /usr/share/fonts/google-noto/NotoSansKhmerUI-Regular.ttf: Noto Sans Khmer UI /usr/share/fonts/khmeros/KhmerOS_sys.ttf: Khmer OS System /usr/share/fonts/khmeros/KhmerOS_battambang.ttf: Khmer OS Battambang /usr/share/fonts/khmeros/KhmerOS_siemreap.ttf: Khmer OS Siemreap /usr/share/fonts/khmeros/KhmerOS_freehand.ttf: Khmer OS Freehand /usr/share/fonts/google-noto/NotoSansKhmer-Regular.ttf: Noto Sans Khmer /usr/share/fonts/khmeros/KhmerOS.ttf: Khmer OS /usr/share/fonts/khmeros/KhmerOS_bokor.ttf: Khmer OS Bokor /usr/share/fonts/khmeros/KhmerOS_content.ttf: Khmer OS Content /usr/share/fonts/google-noto/NotoSansKhmer-Bold.ttf: Noto Sans Khmer /usr/share/fonts/khmeros/KhmerOS_metalchrieng.ttf: Khmer OS Metal Chrieng /usr/share/fonts/google-noto/NotoSerifKhmer-Regular.ttf: Noto Serif Khmer /usr/share/fonts/google-noto/NotoSansKhmerUI-Bold.ttf: Noto Sans Khmer UI /usr/share/fonts/khmeros/KhmerOS_fasthand.ttf: Khmer OS Fasthand /usr/share/fonts/khmeros/KhmerOS_muol.ttf: Khmer OS Muol /usr/share/fonts/khmeros/KhmerOS_muollight.ttf: Khmer OS Muol Light /usr/share/fonts/google-noto/NotoSerifKhmer-Bold.ttf: Noto Serif Khmer /usr/share/fonts/khmeros/KhmerOS_muolpali.ttf: Khmer OS Muol Pali mfabian@ari:~ $
Fonts supporting Khmer available in Fedora are shownin comment#1.
The problem still exists in Fedora-Workstation-netinst-x86_64-25-Alpha-1.2.iso
The problem still exists in Fedora-Workstation-netinst-x86_64-25-20161003.n.0.iso
*** This bug has been marked as a duplicate of bug 1370118 ***