BuddyPress.org

Please use the code button when posting code.

If you are asking for the location of the bp_has_activities function, it is in this file:
buddypress\bp-activity\bp-activity-template.php

You can find the location of a function by searching for them via your code editor.
Or by using google and entering the name of the function.

It should be okay. And just install it to find out for sure.
There is also this one that may be a little better re BP Theme Compat:
https://github.com/boonebgorges/buddypress-skeleton-component/tree/1.7

The best way, for now, is to look thru the codebase for examples of how the BP_Component class is extended to create components.

BuddyPress is not a forum plugin.
BuddyPress uses bbPress for forums.
You may want to ask your question on the bbPress forums.

We have 250,000 users and unless we deactivate BuddyPress – it’s extremely slow with BuddyPress?

I had posted this into forum but with no replies
Yet – current WordPress 5.0 and current BuddyPress.

Cloud SQL is running ar 100% we need to upgrade or contact buddy press team about the issue.
Please contact them and provide the below server details and ask for support.
1. Google Cloud VM Instance Ubuntu 18.04 (3.75 GB RAM)
2. PHP 7.2, Nginx + FastCGI cache, Opcache, Redis, WP-Rocket plugin
3. Cloud SQL for the database (3.75 GB RAM)

If you mean the Private Message button at the top of a profile page, then place this code in bp-custom.php or in your theme > functions.php

function lindsay_profile_button() {
?>
	<div class="generic-button"><a href="https://google.com" >go to google</a></div>
<?php
}
add_action( 'bp_member_header_actions', 'lindsay_profile_button', 25 );

If ‘Private Messaging’ means something else, then you need to talk to the creators of that code because it does not come from BuddyPress.

Did you read https://codex.buddypress.org/developer/function-examples/bp_notifications_add_notification/ ?

You’re right, there is no flag etc.
But having a ‘prevent’ flag on the call would not work, because the actual fetch is performed in the same function that does the grouping.
See get_grouped_notifications_for_user in bp-notifications\classes\class-bp-notifications-notification.php

So a flag that skips the $group_sql in that function would be useful.

You can open an enhancement ticket here. Reference this thread. Even better if you can attach a patch.

As you know, with Buddypress users see an email whenever someone sends them a message and they are offline. We have asked repeatedly to your support if Cometchat overrides BP’s direct messaging function at the basic pricing tier? Because Cometchat email notifications are according to your pricing menu are only available to the highest tier Enterprise pricing and that would cost $12,000 US per year! This functionality is something that Buddypress already does, free, so if CometChat ove rides this functionality then we cannot pay you $12,000 to get it back. Are we missing something? We have tried to ask your support this question but have not received a response. Thank you.

The first thing to do would be to deactivate all other plugins apart from BuddyPress and see if the fault remains. If it does then you need to check if you have overloaded the file by looking in wp-content/themes/your-child-theme/buddypress/members/single/messages/compose.php, if this file exists then check permissions and file content, if it does not exist then check permissions of wp-content/plugins/buddypress/bp-templates/bp-legacy or bp-nouveau/buddypress/members/single/messages/compose.php

PeepSo made a copy of BuddyPress and turned it commercial, as you pretty much describe.