Initial code for exporting a template CSV with headers.

salesforce/my-conservation-life/force-app/main/default/lwc/exportHeaders/exportHeaders.html

+<template>
+    <lightning:layout horizontalalign="space">
+        <lightning:layoutItem size="10">
+            <lightning-combobox
+                name="datasource"
+                label="Export a template CSV"
+                value={value}
+                placeholder={value}
+                options={combo_options}
+                onchange={handleChange}
+            ></lightning-combobox>
+        </lightning:layoutItem>
+        <br/>
+        <lightning:layoutItem size="2">
+            <lightning-button variant="success" label="Download" onclick={download}></lightning-button>
+        </lightning:layoutItem>
+    </lightning:layout>
+</template>

salesforce/my-conservation-life/force-app/main/default/lwc/exportHeaders/exportHeaders.js

+import { LightningElement, track } from 'lwc';
+import { assetDefinitions } from 'c/controllers';
+
+export default class ExportHeaders extends LightningElement {
+
+    @track value = 'Select an asset type...';
+    @track valueID = null;
+    @track placeholder = 'N/A';
+    @track combo_options = [];
+
+    /**
+     * Sets the combobox options.
+     */
+    connectedCallback() {
+        var i;
+        assetDefinitions.fetchAssetTypes()
+            .then(data => {
+                var temp_options = [];
+                for (i = 0; i < data.rows.length; i++) {
+                    temp_options.push({
+                        'label': data.rows[i]['name'] + ': ' + data.rows[i]['id'],
+                        'value': data.rows[i]['name'] + ': ' + data.rows[i]['id']
+                    });
+                }
+                this.combo_options = temp_options;
+            })
+            .catch(e => {
+                console.log('Exception: ', e);
+            });
+    }
+
+    /**
+     * Event handler for when something is selected from the combobox.
+     * @param {*} event - the event object
+     */
+    handleChange(event) {
+        this.value = event.detail.value;
+        this.valueID = event.detail.value.split(':')[1].trimLeft();
+    }
+
+    /**
+     * Event handler for when the download button is pressed.
+     */
+    download() {
+        var i;
+        var csv_data = '';
+        var rows = [];
+        var hiddenElement;
+
+        assetDefinitions.fetchAssetPropTypes(this.valueID)
+            .then(properties => {
+                rows = ['asset_id'];
+                for (i = 0; i < properties.rows.length; i++) {
+                    rows.push(properties.rows[i]['name']);
+                }
+                csv_data += rows.join(',') + '\n';
+
+                // Creates the CSV file and downloads it.
+                hiddenElement = document.createElement('a');
+                hiddenElement.href = 'data:text/csv;charset=utf-8,' + encodeURI(csv_data);
+                hiddenElement.target = '_blank';
+                hiddenElement.download = this.value + '_template.csv';
+                hiddenElement.click();
+            })
+            .catch(e => {
+                console.log('Exception: ', e);
+            });
+    }
+}

salesforce/my-conservation-life/force-app/main/default/lwc/exportHeaders/exportHeaders.js-meta.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<LightningComponentBundle xmlns="http://soap.sforce.com/2006/04/metadata">
+    <apiVersion>47.0</apiVersion>
+    <isExposed>true</isExposed>
+    <targets>
+        <target>lightning__AppPage</target>
+        <target>lightning__RecordPage</target>
+        <target>lightning__HomePage</target>
+    </targets>
+</LightningComponentBundle>

salesforce/my-conservation-life/sfdx-project.json

@@ -7,5 +7,5 @@
   ],
   "namespace": "",
   "sfdcLoginUrl": "https://login.salesforce.com",
-  "sourceApiVersion": "48.0"
+  "sourceApiVersion": "47.0"
 }