EmberConf 2021 companion app timezone converter. Open the Schedule page in the companion app, paste this code snippet into the Dev Tools console., change your time zone (first line) and run

code.js

yourTimeZoneUtc = 3;

emberConfTimeZoneUtc = -7;

//////////

function getTime(str) {
  const [_str, hoursRawStr, minutesStr, amPm] = /(\d+):(\d+) (\w+)/.exec(str); 
  const hoursRaw = parseInt(hoursRawStr, 10);
  const isPm = amPm === 'PM';

  // https://stackoverflow.com/a/15083891/901944
  const hours =
    (isPm && hoursRaw < 12)    ? hoursRaw + 12 :
    (!isPm && hoursRaw === 12) ? 0             :
                                 hoursRaw;

  const hoursNew = (hours + yourTimeZoneUtc - emberConfTimeZoneUtc + 24) % 24;

  return `${hoursNew}:${minutesStr}`;
}

/////////

function changeTime(element) {
  const newTime = getTime(element.textContent.trim());
  element.textContent = newTime;
}

/////////

Array
  .from(document.querySelectorAll('.full-schedule-item__time'))
  .forEach(element => {
    changeTime(element.children[0]);
    changeTime(element.children[1]);
  });

LICENCE.md

BSD Zero Clause License (public-domain-equivalent)

Copyright (C) 2021 by Andrey Mikhaylov (lolmaus) lolmaus@gmail.com

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.