[Samsung Galaxy A10 Questions & Answers] richaardvark:
I've decompiled the SecSettings.apk app and here are all the references to the OEM bootloader unlock that I have found, and the file location/name which contains the mention:

File:

SecSettings/res/values/strings.xml

Found items:

<string name="sec_confirm_disable_oem_unlock_text_new">If OEM unlock is turned off, your phone will be reset to its factory default settings after you restart it. This will erase all of your data, including files and downloaded apps. Device protection functions will work after your phone is reset.</string>
<string name="sec_confirm_disable_oem_unlock_title_new">Turn off OEM unlock?</string>
<string name="sec_confirm_enable_oem_unlock_text_new">"If OEM unlock is turned on, your phone will be reset to its factory default settings after you restart it. This will erase all of your data, including files and downloaded apps. Device protection functions won't work, and secure apps such as Knox and Samsung Pay will be disabled if you use a custom OS."</string>
<string name="sec_confirm_enable_oem_unlock_title_new">Turn on OEM unlock?</string>
<string name="oem_lock_info_message">Please restart the device to enable device protection feature.</string>
<string name="oem_preferred_feedback_reporter" />
<string name="oem_radio_info_label">OEM-specific Info/Settings</string>
<string name="oem_unlock_enable">OEM unlocking</string>
<string name="oem_unlock_enable_disabled_summary_bootloader_unlocked">Bootloader is already unlocked</string>
<string name="oem_unlock_enable_disabled_summary_connectivity">Connect to the internet first</string>
<string name="oem_unlock_enable_disabled_summary_connectivity_or_locked">Connect to the internet or contact your carrier</string>
<string name="oem_unlock_enable_disabled_summary_sim_locked_device">Unavailable on carrier-locked devices</string>
<string name="oem_unlock_enable_summary">Allow the bootloader to be unlocked</string>

File:

SecSettings/res/values/public.xml

Found items:

<public type="string" name="confirm_enable_oem_unlock_text" id="0x7f120547" />
<public type="string" name="confirm_enable_oem_unlock_title" id="0x7f120548" />
<public type="string" name="oem_lock_info_message" id="0x7f121045" />
<public type="string" name="oem_preferred_feedback_reporter" id="0x7f121046" />
<public type="string" name="oem_radio_info_label" id="0x7f121047" />
<public type="string" name="oem_unlock_enable" id="0x7f121048" />
<public type="string" name="oem_unlock_enable_disabled_summary_bootloader_unlocked" id="0x7f121049" />
<public type="string" name="oem_unlock_enable_disabled_summary_connectivity" id="0x7f12104a" />
<public type="string" name="oem_unlock_enable_disabled_summary_connectivity_or_locked" id="0x7f12104b" />
<public type="string" name="oem_unlock_enable_disabled_summary_sim_locked_device" id="0x7f12104c" />
<public type="string" name="oem_unlock_enable_summary" id="0x7f12104d" />
<public type="string" name="sec_confirm_disable_oem_unlock_text_new" id="0x7f1213f0" />
<public type="string" name="sec_confirm_disable_oem_unlock_title_new" id="0x7f1213f1" />
<public type="string" name="sec_confirm_enable_oem_unlock_text_new" id="0x7f1213f2" />
<public type="string" name="sec_confirm_enable_oem_unlock_title_new" id="0x7f1213f3" />

File:

SecSettings/res/xml/development_settings.xml

Found items:

<com.android.settingslib.RestrictedSwitchPreference android:title="@string/oem_unlock_enable" android:key="oem_unlock_enable" android:summary="@string/oem_unlock_enable_summary" settings:useAdditionalSummary="true" />

File:

SecSettings/AndroidManifest.xml

Found items:

<uses-permission android:name="android.permission.OEM_UNLOCK_STATE"/>
<uses-permission android:name="android.permission.MANAGE_USER_OEM_UNLOCK_STATE"/>

There are a couple of other SecSettings apps... I'll go through them as well and report back.