diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0525f4d..1dcfa32 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,9 @@
 - The `channel add/remove` commands now show a message about the result of the command.
 - The instructions for setting the Simtropolis authentication cookie have been moved to the file
   [sc4pac.bat](https://github.com/memo33/sc4pac-tools/blob/main/src/scripts/sc4pac.bat#L13-L32).
+- The default `include` filter has been changed to include only plugin files (`.sc4*`/`.dat`/`.dll`) instead of arbitrary file extensions.
+  This ensures that non-plugin files are not accidentally installed if a custom `exclude` filter is specified.
+  (The default `exclude` filter remains unchanged and excludes any non-plugin files (`.sc4*`/`.dat`/`.dll`).)
 
 ### Fixed
 - a bug causing assets containing Clickteam installers to be reinstalled whenever running `sc4pac update`.
diff --git a/channel-testing/yaml/templates/package-template-basic.yaml b/channel-testing/yaml/templates/package-template-basic.yaml
index b828096..ce045c3 100644
--- a/channel-testing/yaml/templates/package-template-basic.yaml
+++ b/channel-testing/yaml/templates/package-template-basic.yaml
@@ -39,7 +39,7 @@ assets:  # Optional list of assets from which to extract files (zero or more)
   # (starting with and separated by _forward_ slashes for platform independence).
   # Note that special characters need to be escaped: \.[]{}()<>*+-=!?^$| (see https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html).
   # The matching is case-insensitive for file-system independence.
-  # By default, every file is included.
+  # By default, every plugin file is included (.dat/.sc4model/.sc4lot/.sc4desc/.sc4/.dll).
   include:
   - "/folder/file1.dat"
   - "/folder2/"
diff --git a/src/main/scala/sc4pac/Constants.scala b/src/main/scala/sc4pac/Constants.scala
index b2c121a..b28ae25 100644
--- a/src/main/scala/sc4pac/Constants.scala
+++ b/src/main/scala/sc4pac/Constants.scala
@@ -10,7 +10,7 @@ object Constants {
   val link = new Configuration("link")  // extends `compile` with actual assets (TODO rename to `install`?)
   export JsonRepoUtil.sc4pacAssetOrg  // val sc4pacAssetOrg = Organization("sc4pacAsset")
   val sc4pacAssetType = Type("sc4pac-resource")  // TODO
-  val defaultInclude = """."""  // includes everything
+  val defaultInclude = """(?<=\.dat|\.sc4model|\.sc4lot|\.sc4desc|\.sc4|\.dll)$"""  // includes only plugin files
   val defaultExclude = """(?<!\.dat|\.sc4model|\.sc4lot|\.sc4desc|\.sc4|\.dll)$"""  // excludes files with other file types
   val sc4fileTypePattern = Pattern.compile("""\.dat|\.sc4model|\.sc4lot|\.sc4desc|\.sc4|\.dll$""", Pattern.CASE_INSENSITIVE)
   val versionLatestRelease = "latest.release"