Is ExpressKeys: Password Manager safe?

const defaultSettings = {
  helpImprove: true
};

async function initMixpanel(helpImproveEnabled) {
  try {
    const [distinctId, { mixpanelOptedIn }, superProps] = await Promise.all([
      getOrCreateDistinctId(),
      chrome.storage.local.get("mixpanelOptedIn"),
      buildSuperProperties()
    ]);
    const client = new MixpanelClient({
      token: "23920fee3c3395f197c9514016713848",
      host: "https://qm.cp.expressapisv2.net",
      distinctId,
      optOutByDefault: true,
      debug: false,
      superProperties: superProps
    });
    if (helpImproveEnabled) {
      if (mixpanelOptedIn) {
        client.restoreOptIn();
      } else {
        await client.optIn();
        await chrome.storage.local.set({ mixpanelOptedIn: true });
      }
    }
    mixpanelInstance = client;
  } catch (err) {
    console.error("[Mixpanel Init] Failed to initialize:", err);
  }
}

async sendBatch(events) {
  if (events.length === 0) return;
  const payload = events.map(e => e.data);
  const encoded = btoa(JSON.stringify(payload));
  const url = `${this.host}/track?data=${encodeURIComponent(encoded)}`;
  let attempt = 0, lastError = null;
  while (attempt <= this.ingestion.maxRetries) {
    try {
      const res = await fetch(url, {
        method: "GET",
        headers: { "Content-Type": "application/json" }
      });
      if (!res.ok) {
        if (res.status === 400) throw new Error(`Validation error: ${res.status}`);
        if (res.status === 429 || res.status >= 500) throw new Error(`Transient error: ${res.status}`);
        if (res.status >= 400 && res.status < 500) throw new Error(`Client error: ${res.status}`);
      }
      const text = await res.text();
      if (text.trim() === "1") {
        this.log(`[Mixpanel] Batch of ${events.length} events sent`);
        return;
      } else {
        throw text.trim() === "0"
          ? new Error("Mixpanel returned failure response")
          : new Error(`Unexpected response: ${text}`);
      }
    } catch (err) {
      lastError = err;
      attempt++;
      if (err instanceof TypeError ||
          lastError.message.includes("Validation error") ||
          lastError.message.includes("Client error") ||
          lastError.message.includes("Mixpanel returned failure")) {
        throw err;
      }
      if (attempt <= this.ingestion.maxRetries) {
        const delay = this.calculateRetryDelay(attempt);
        this.log(`[Mixpanel] Retry attempt ${attempt} after ${delay}ms`);
        await this.sleep(delay);
      }
    }
  }
  throw new Error(`Max retries exceeded. Last error: ${lastError?.message}`);
}