koj only recently (2 ed ago?) started removing kanwa stuff from its single-kanji entries, and there's still a mix of some kanwa stuff in there that's not supported by any other source.  by itself, it's not a reliable source for entries that could be kanwa, such as 試.  no need for 2 senses, i think.

n-pref is for entries where the kokugo officially labels the PoS as a noun, but notes 接頭に or similar.  there's probably really no need to distinguish it from pref, but we do, so i guess that's how

@@ -12,2 +12 @@
-<pos>&pref;</pos>
-<gloss>trial</gloss>
+<gloss>testing</gloss>
@@ -16,5 +14,0 @@
-</sense>
-<sense>
-<pos>&n;</pos>
-<xref type="see" seq="1312350">試験・1</xref>
-<misc>&abbr;</misc>
@@ -23 +17 @@
-<gloss>test</gloss>
+<gloss>trial</gloss>

@@ -19 +19 @@
-<xref type="see" seq="1312350">試験</xref>
+<xref type="see" seq="1312350">試験・1</xref>

daijs & nikk: ためすこと。試験。https://kotobank.jp/word/試-515190
koj: ①ためすこと。②試験の略。

sense 1: 試運転
sense 2: https://furigana.info/w/試:し

what is the difference between pref and n-pref?