No need to use strip here, just remove the last character

themeSwitcher.nim

@@ -1,6 +1,6 @@
 from std/osproc import execProcess, ProcessOption, startProcess, waitForExit, close
 from std/os import symlinkExists, getConfigDir, putEnv, `/`
-from std/strutils import split, endsWith, strip
+from std/strutils import split, endsWith
 from std/strformat import fmt
 import owlkettle
 
@@ -64,7 +64,7 @@ viewable App:
     build:
       let currentTheme: string = execProcess("/usr/bin/xfconf-query",
         args=["--channel=xsettings", "--property=/Net/ThemeName"],
-        options={}).strip(leading=false, trailing=true, chars={'\n'})
+        options={})[0 .. ^2]
 
       let currentThemeSplit: seq[string] = currentTheme.split('-', 2)