diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 52e4aefb6b7..c64d91a7ebb 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -183,7 +183,7 @@ Here's how to run the test suite:
 ## Translation
 
 All translation work happens on [Crowdin](https://translate.gitea.com).
-The only translation that is maintained in this repository is [the English translation](https://github.com/go-gitea/gitea/blob/main/options/locale/locale_en-US.ini).
+The only translation that is maintained in this repository is [the English translation](https://github.com/go-gitea/gitea/blob/main/options/locale/locale_en-US.json).
 It is synced regularly with Crowdin. \
 Other locales on main branch **should not** be updated manually as they will be overwritten with each sync. \
 Once a language has reached a **satisfactory percentage** of translated keys (~25%), it will be synced back into this repo and included in the next released version.
diff --git a/build/backport-locales.go b/build/backport-locales.go
deleted file mode 100644
index d112dd72bd5..00000000000
--- a/build/backport-locales.go
+++ /dev/null
@@ -1,115 +0,0 @@
-// Copyright 2023 The Gitea Authors. All rights reserved.
-// SPDX-License-Identifier: MIT
-
-//go:build ignore
-
-package main
-
-import (
-	"fmt"
-	"os"
-	"os/exec"
-	"path/filepath"
-	"strings"
-
-	"code.gitea.io/gitea/modules/container"
-	"code.gitea.io/gitea/modules/setting"
-)
-
-func main() {
-	if len(os.Args) != 2 {
-		println("usage: backport-locales <to-ref>")
-		println("eg: backport-locales release/v1.19")
-		os.Exit(1)
-	}
-
-	mustNoErr := func(err error) {
-		if err != nil {
-			panic(err)
-		}
-	}
-	collectInis := func(ref string) map[string]setting.ConfigProvider {
-		inis := map[string]setting.ConfigProvider{}
-		err := filepath.WalkDir("options/locale", func(path string, d os.DirEntry, err error) error {
-			if err != nil {
-				return err
-			}
-			if d.IsDir() || !strings.HasSuffix(d.Name(), ".ini") {
-				return nil
-			}
-			cfg, err := setting.NewConfigProviderForLocale(path)
-			mustNoErr(err)
-			inis[path] = cfg
-			fmt.Printf("collecting: %s @ %s\n", path, ref)
-			return nil
-		})
-		mustNoErr(err)
-		return inis
-	}
-
-	// collect new locales from current working directory
-	inisNew := collectInis("HEAD")
-
-	// switch to the target ref, and collect the old locales
-	cmd := exec.Command("git", "checkout", os.Args[1])
-	cmd.Stdout = os.Stdout
-	cmd.Stderr = os.Stderr
-	mustNoErr(cmd.Run())
-	inisOld := collectInis(os.Args[1])
-
-	// use old en-US as the base, and copy the new translations to the old locales
-	enUsOld := inisOld["options/locale/locale_en-US.ini"]
-	brokenWarned := make(container.Set[string])
-	for path, iniOld := range inisOld {
-		if iniOld == enUsOld {
-			continue
-		}
-		iniNew := inisNew[path]
-		if iniNew == nil {
-			continue
-		}
-		for _, secEnUS := range enUsOld.Sections() {
-			secOld := iniOld.Section(secEnUS.Name())
-			secNew := iniNew.Section(secEnUS.Name())
-			for _, keyEnUs := range secEnUS.Keys() {
-				if secNew.HasKey(keyEnUs.Name()) {
-					oldStr := secOld.Key(keyEnUs.Name()).String()
-					newStr := secNew.Key(keyEnUs.Name()).String()
-					broken := oldStr != "" && strings.Count(oldStr, "%") != strings.Count(newStr, "%")
-					broken = broken || strings.Contains(oldStr, "\n") || strings.Contains(oldStr, "\n")
-					if broken {
-						brokenWarned.Add(secOld.Name() + "." + keyEnUs.Name())
-						fmt.Println("----")
-						fmt.Printf("WARNING: skip broken locale: %s , [%s] %s\n", path, secEnUS.Name(), keyEnUs.Name())
-						fmt.Printf("\told: %s\n", strings.ReplaceAll(oldStr, "\n", "\\n"))
-						fmt.Printf("\tnew: %s\n", strings.ReplaceAll(newStr, "\n", "\\n"))
-						continue
-					}
-					secOld.Key(keyEnUs.Name()).SetValue(newStr)
-				}
-			}
-		}
-		mustNoErr(iniOld.SaveTo(path))
-	}
-
-	fmt.Println("========")
-
-	for path, iniNew := range inisNew {
-		for _, sec := range iniNew.Sections() {
-			for _, key := range sec.Keys() {
-				str := sec.Key(key.Name()).String()
-				broken := strings.Contains(str, "\n")
-				broken = broken || strings.HasPrefix(str, "`") != strings.HasSuffix(str, "`")
-				broken = broken || strings.HasPrefix(str, "\"`")
-				broken = broken || strings.HasPrefix(str, "`\"")
-				broken = broken || strings.Count(str, `"`)%2 == 1
-				broken = broken || strings.Count(str, "`")%2 == 1
-				if broken && !brokenWarned.Contains(sec.Name()+"."+key.Name()) {
-					fmt.Printf("WARNING: found broken locale: %s , [%s] %s\n", path, sec.Name(), key.Name())
-					fmt.Printf("\tstr: %s\n", strings.ReplaceAll(str, "\n", "\\n"))
-					fmt.Println("----")
-				}
-			}
-		}
-	}
-}