Use colorprofiles package, the used profile FOGRA39L Coated is contained in that package

liuthesis.cls

@@ -308,7 +308,7 @@
 \RequirePackage{pbox}
 \RequirePackage{ifthen}
 \RequirePackage{geometry}
-%%%%%%%%%% PDF/A support
+%%%%%%%%%% PDF/A and PDF/X support
 % https://tex.stackexchange.com/questions/474197/pdfx-incomplete-cidset-in-some-fonts/474336#474336
 \ifluatex
 \pdfvariable omitcidset=1
@@ -316,14 +316,14 @@
 \RequirePackage[pdfa,pdfusetitle,bookmarks=false]{hyperref} %bookmarks are incompatible with PDF/X<6
 \RequirePackage{hyperxmp}[2020/06/15]
 \RequirePackage{cmap}
-
+\RequirePackage{colorprofiles}
 \ifxetex
   \def\OBJ@CMYK{@colorprofile}%
-  \immediate\special{pdf:fstream \OBJ@CMYK (FOGRA39L_coated.icc) <</N 4>>}%
+  \immediate\special{pdf:fstream \OBJ@CMYK (\colorpro@cmyk@profile) <</N 4>>}%
   \def\pdfcatalog#1{\special{pdf:put @catalog <<#1>>}}
   \def\pdfpageattr#1{\special{pdf:put @thispage <<#1>>}}
 \else
-  \immediate\pdfobj stream attr{/N 4} file {FOGRA39L_coated.icc}%
+  \immediate\pdfobj stream attr{/N 4} file {\colorpro@cmyk@profile}%
   \edef\OBJ@CMYK{\the\pdflastobj\space 0 R}%
 \fi
 \pdfcatalog{%
@@ -331,38 +331,34 @@
     /Type /OutputIntent
     /S/GTS_PDFA1
     /DestOutputProfile \OBJ@CMYK
-    /OutputConditionIdentifier (Coated FOGRA39)
+    /OutputConditionIdentifier (\colorpro@cmyk@intent)
     /Info(FOGRA39L)
-    /OutputCondition(Offset printing, according to ISO 12647-2:2004/Amd 1, OFCOM, paper type 1 or 2 = coated art, 115 g/m2, tone value increase curves A (CMY) and B (K))
-    /RegistryName(http://www.fogra.org)
+    /OutputCondition(\colorpro@cmyk@identifier)
+    /RegistryName(\colorpro@cmyk@registry)
   >>
   <<
     /Type /OutputIntent
     /S/GTS_PDFX
     /DestOutputProfile \OBJ@CMYK
-    /OutputConditionIdentifier (Coated FOGRA39)
+    /OutputConditionIdentifier (\colorpro@cmyk@intent)
     /Info(FOGRA39L)
-    /OutputCondition(Offset printing, according to ISO 12647-2:2004/Amd 1, OFCOM, paper type 1 or 2 = coated art, 115 g/m2, tone value increase curves A (CMY) and B (K))
-    /RegistryName(http://www.fogra.org)
+    /OutputCondition(\colorpro@cmyk@identifier)
+    /RegistryName(\colorpro@cmyk@registry)
   >> ]
 }
-
 % Bugfix of hyperref to produce CMYK links
 \let\HyColor@HyperrefBorderColor\HyColor@XZeroOneThreeFour
-
-%we need to tell PDF/X the final format of the paper. This needs adjustment if you want graphics on the page border, called bleeding
+% Tell PDF/X the final format of the paper
 \@tempdima=0.99626400996264009962\paperwidth
 \edef\boxwd{\strip@pt\@tempdima}
 \@tempdima=0.99626400996264009962\paperheight
 \edef\boxht{\strip@pt\@tempdima}
-
 \edef\next{%
   \protect\pdfpageattr{
     /TrimBox[0.0 0.0 \boxwd\space \boxht]
   }%
 }
 \next
-
 \hypersetup{%
     pdfdisplaydoctitle=true,
     pdftrapped=False,
@@ -371,8 +367,7 @@
     pdfuapart=1,
     pdfxstandard={PDF/X-4},
 }
-
-%%%%%%%%%% end PDF/A support
+%%%%%%%%%% end PDF/A and PDF/X support
 \RequirePackage{amssymb}
 \RequirePackage{amsmath}
 \RequirePackage{etoolbox}