I lost access to my old account, and people were asking for 1.12, 1.13, and 1.14 updates, so here is the first update.
Version 1.9_1.0.2 works on 1.9-1.12.2.
Version 1.13_1.0.2 works on 1.13.x-1.15.x

When you first ignite a Nether portal, you will see this message.

When the portals are linked, at least one side will show this message.

PortalHelper helps players link portals.
Commands:

  /PH Link - Displays on screen if your current location
             will properly sync with a nether portal
  OP Commands
  /PH Update - Check for update.
  /PH Reload - Reloads this plugin.
  /PH td - Temporarily toggles debug.

Permissions:

portalhelper.config:
description: Allows player to change configs.
default: false
portalhelper.linkcommand:
description: Allows player to use /ph link command.
default: false
portalhelper.rightclick:
description: Allows player to use right click portal detection.
default: false
portalhelper.showUpdateAvailable:
description: Shows player that there is a version update.
default: op

Config:

# Change to false to stop auto-update-check.
auto_update_check: true

# Set to true before sending a log about an issue.
# Logs trace data required to pinpoint where errors are.
debug: false

# Set the language to use, cs-CZ, de_DE, en_US, es_MX, fr_FR, lol_US, nl_NL, pt_BR, zh_CN, zh_TW
lang: en_US

For help you can post issues and suggest ideas on my discord server.

This plugin is open source; you can view the source code on github. Feel free to open issues there or submit pull requests.

This plugin utilizes bStats to collect anonymous statistics