diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 0e046e9d5..57c57b62b 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -14,6 +14,11 @@ repos:
     rev: v8.20.1
     hooks:
       - id: gitleaks
+  - repo: https://github.com/shssoichiro/oxipng
+    rev: v9.1.2
+    hooks:
+      - id: oxipng
+        args: ["-o", "4", "--strip", "safe", "--alpha"]
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v5.0.0
     hooks:
@@ -22,6 +27,8 @@ repos:
       - id: check-executables-have-shebangs
         exclude: ^test/t/lang\.rb$
       - id: check-illegal-windows-names
+      - id: pretty-format-json
+        args: [--autofix, --no-sort-keys]
       - id: check-json
       - id: check-merge-conflict
       - id: check-shebang-scripts-are-executable
diff --git a/doc/mruby_logo_red_icon.png b/doc/mruby_logo_red_icon.png
index 9006c84eb..e36f34a1f 100644
Binary files a/doc/mruby_logo_red_icon.png and b/doc/mruby_logo_red_icon.png differ
diff --git a/mrbgems/mruby-bigint/core/bigint.c b/mrbgems/mruby-bigint/core/bigint.c
index 422969295..94e168b66 100644
--- a/mrbgems/mruby-bigint/core/bigint.c
+++ b/mrbgems/mruby-bigint/core/bigint.c
@@ -248,9 +248,11 @@ static int
 uzero_p(mpz_t *x)
 {
   if (x->sz == 0) return 1;
-  for (size_t i=x->sz-1; 0 <= i; i--)
+  for (size_t i=x->sz-1;; i--) {
     if (x->p[i] != 0)
       return 0;
+    if (i == 0) break;
+  }
   return 1;
 }
 
diff --git a/src/array.c b/src/array.c
index 55b78fbe6..af9aa917d 100644
--- a/src/array.c
+++ b/src/array.c
@@ -1275,12 +1275,6 @@ mrb_ary_clear(mrb_state *mrb, mrb_value self)
   return self;
 }
 
-static mrb_value
-mrb_ary_clear_m(mrb_state *mrb, mrb_value self)
-{
-  return mrb_ary_clear(mrb, self);
-}
-
 static mrb_value
 mrb_ary_empty_p(mrb_state *mrb, mrb_value self)
 {
@@ -1681,7 +1675,7 @@ mrb_init_array(mrb_state *mrb)
   mrb_define_method_id(mrb, a, MRB_OPSYM(lshift),        mrb_ary_push_m,       MRB_ARGS_REQ(1));   /* 15.2.12.5.3  */
   mrb_define_method_id(mrb, a, MRB_OPSYM(aref),          mrb_ary_aget,         MRB_ARGS_ARG(1,1)); /* 15.2.12.5.4  */
   mrb_define_method_id(mrb, a, MRB_OPSYM(aset),          mrb_ary_aset,         MRB_ARGS_ARG(2,1)); /* 15.2.12.5.5  */
-  mrb_define_method_id(mrb, a, MRB_SYM(clear),           mrb_ary_clear_m,      MRB_ARGS_NONE());   /* 15.2.12.5.6  */
+  mrb_define_method_id(mrb, a, MRB_SYM(clear),           mrb_ary_clear,        MRB_ARGS_NONE());   /* 15.2.12.5.6  */
   mrb_define_method_id(mrb, a, MRB_OPSYM(cmp),           mrb_ary_cmp,          MRB_ARGS_REQ(1));
   mrb_define_method_id(mrb, a, MRB_SYM(concat),          mrb_ary_concat_m,     MRB_ARGS_REQ(1));   /* 15.2.12.5.8  */
   mrb_define_method_id(mrb, a, MRB_SYM(delete),          mrb_ary_delete,       MRB_ARGS_REQ(1));