diff --git a/printer.py b/printer.py
index 8e81390..5fd517e 100644
--- a/printer.py
+++ b/printer.py
@@ -315,7 +315,10 @@ class PrinterDriver(Commander):
 
     def loop(self, *futures):
         ''' Run coroutines in order in current event loop until complete,
-            return its result directly, or their result as tuple
+            return its result directly, or their result as tuple.
+
+            This 1) ensures exiting gracefully (futures always get completed before exiting),
+            and 2) avoids function colors (use of "await", especially outside this script)
         '''
         results = []
         for future in futures:
@@ -344,9 +347,9 @@ class PrinterDriver(Commander):
         self.model = Models[name]
         self.device = BleakClient(address)
         def notify(_char, data):
-            if data == b'\x51\x78\xae\x01\x01\x00\x10\x70\xff':
+            if data == self.data_flow_pause:
                 self._paused = True
-            elif data == b'\x51\x78\xae\x01\x01\x00\x00\x00\xff':
+            elif data == self.data_flow_resume:
                 self._paused = False
         self.loop(
             self.device.connect(timeout=self.connection_timeout),
@@ -371,6 +374,7 @@ class PrinterDriver(Commander):
                 name, address = identifier.split(',')
                 if name not in Models:
                     error('model-0-is-not-supported-yet', name, exception=PrinterError)
+                # TODO: is this logic correct?
                 if address[2::3] != ':::::' and len(address.replace('-', '')) != 32:
                     error('invalid-address-0', address, exception=PrinterError)
                 if use_result:
diff --git a/printer_lib/commander.py b/printer_lib/commander.py
index 6604707..04af2c9 100644
--- a/printer_lib/commander.py
+++ b/printer_lib/commander.py
@@ -1,5 +1,5 @@
 '''
-Cat-Printer Commander, way to communicate with cat printers via bluetooth
+Cat-Printer Commander(s), binary interface(s) to communicate with cat printers
 
 No rights reserved.
 License CC0-1.0-only: https://directory.fsf.org/wiki/License:CC0
@@ -65,10 +65,17 @@ def int_to_bytes(i: int, big_endian=False):
     return result
 
 class Commander(metaclass=ABCMeta):
-    'Semi-abstract class, to be inherited by `PrinterDriver`'
+    ''' Semi-abstract class, to be inherited by `PrinterDriver`
+        Contains binary data communication interface for individual functions
+        "Commander" of kind of printers like GB0X, GT01
+        Class structure is not guaranteed to be stable
+    '''
 
     dry_run: bool = False
 
+    data_flow_pause = b'\x51\x78\xae\x01\x01\x00\x10\x70\xff'
+    data_flow_resume = b'\x51\x78\xae\x01\x01\x00\x00\x00\xff'
+
     def make_command(self, command_bit, payload: bytearray, *,
                      prefix=bytearray(), suffix=bytearray()):
         'Make bytes that to be used to control printer'
diff --git a/www/index.html b/www/index.html
index 65ef0ed..e80736f 100644
--- a/www/index.html
+++ b/www/index.html
@@ -45,7 +45,7 @@
                             <span data-i18n="brightness-">Brightness:</span>
                             <input type="range" min="0" max="256" value="86" step="16" name="threshold" data-key data-default />
                         </label>
-                        <!-- "Strength", so-called "darkness", or internally "energy" -->
+                        <!-- Thermal "Strength", so-called "darkness", or internally "energy" -->
                         <label class="label-span-input" data-hide-as="print">
                             <span data-i18n="strength-">Strength:</span>
                             <input type="range" min="0" max="256" value="64" step="16" name="energy" data-key data-default />
@@ -147,7 +147,7 @@
         </div>
     </main>
     <div id="hidden" class="hard-hidden">
-        <!-- Hidden area for putting elements -->
+        <!-- Hidden area for putting dynamic elements -->
         <input type="file" id="file" />
         <img src="" id="img" alt="hidden-image" />
         <div id="accessibility">
diff --git a/www/main.js b/www/main.js
index ae2d267..6dda0d6 100644
--- a/www/main.js
+++ b/www/main.js
@@ -822,7 +822,7 @@ class Main {
 
             if (this.settings['is_android']) {
                 document.body.classList.add('android');
-                // select[multiple] doesn't work well with Android
+                // select[multiple] doesn't work well with Android WebView
                 let div = document.createElement('div');
                 let select = document.getElementById('select-language');
                 Array.from(select.children).forEach(e => {