You're using a custom asset so you'd need to implement custom template code for parsing that asset into whatever it's supposed to be. The template files in the below location handle preparing source objects, determining access, and parsing the display of all core activity.

/components/com_comprofiler/plugin/user/plug_cbactivity/templates/default/core

You can add to those files in a custom CB Activity template. Simply create "custom" folder in the templates folder. Next copy the "core" folder from default to "custom". Now in CB Activity select "custom" as the template. You can now freely modify the core parsing to add your own. Note you will want to DIFF these against the defaults when a new release is made encase fixes have been applied.

Will be reviewing how to better handle this in a future release, but for now it's either through template files or through code so you could use CB Auto Actions to parse the activity instead, but that's a bit more complicated. In a future release I want to figure out some sort of management page in backend where you can supply necessary PHP, SQL, or something of the sort for parsing custom activity assets.

For custom source parsing you'd use the activity_onAssetSource trigger. Source parsing lets CB Activity know what object is in relation to the activity. So for example GJ uses it to tell CB Activity we've a group object as the source for group activity. Example of its usage as follows.

Global
Triggers: activity_onAssetSource
Type: Code
User: Automatic
Access: Everybody
Conditions
Field: Custom > Value
Custom Value: [var1]
Operator: Is REGEX
Value: /hotspot\.\d+/
Action
Method: PHP
Code:Parameters
References: Variable 2

You'll need to write the necessary PHP and set var2 to it. I've no idea what that might be for whatever your hotspots are, but you'd replace SOURCE_OBJECT_HERE with that source object. This is typically done by pulling the id from the asset using REGEXP then preparing an object from that. This has the benefit of all CB Activity API when calling the source API it knows the object already. That includes the activity_onAfterCreateStreamActivity trigger where var2 is the source object. That triggers variables are as follows.


The above isn't necessary for custom activity display parsing, but I'm just describing the process that CB GroupJive goes through.

As for display parsing you'd use the activity_onDisplayStreamActivity trigger as its name suggests. Same concept as above. We need to modify the data by references. Example as follows.

Global
Triggers: activity_onDisplayStreamActivity
Type: Code
User: Automatic
Access: Everybody
Conditions
Field: Custom > Value
Custom Value: [var1_asset]
Operator: Is REGEX
Value: /hotspot\.\d+/
Action
Method: PHP
Code:Parameters
References: Variable 2, Variable 4, Variable 5

Variables 2 and 4 are the activity title and message. If you need to insert custom HTML content use variable 5. This triggers variables are as follows.


If you implemented the source parsing then you can use $variables->source() to get your hotspot object otherwise you'll have to add the code at this time in your display parsing PHP.